JPS5935799B2 - Recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording method using a recording material having a heat-sensitive layer that becomes insolubilized by irradiation with laser light.

More specifically, the present invention relates to a recording method that requires less recording energy, can obtain clear images, and can use recording materials with strong film strength. A thermal (heat mode) recording material is known in which when a high-density energy light such as a laser beam is irradiated, the heat-sensitive layer becomes insolubilized, melted, evaporated, or burned by the heat of the high-density energy light, and records are recorded. There is.

A method of irradiating high-density energy light in such a recording method on a thermal recording material is, for example, converting the information to be recorded into an electrical time-series signal, modulating the laser light according to the signal, and There are methods such as scanning a recording material with a modulated laser beam, and it is possible to perform recording with extremely short irradiation. Such a recording system has advantages in terms of speed of information processing and economy. Conventionally, such a thermal recording material is known, for example, as described in Japanese Patent Publication No. 46-40479, the recording layer is composed of three layers of germanium, bismuth, and selenium.

In addition, a heat-sensitive recording material provided with a layer for reducing heat conduction between a recording layer and its support was disclosed in Japanese Patent Application Laid-Open No. 50-126237.
It is stated in the No. In addition, special public service 51-1426
Publication No. 3 also describes a heat-sensitive recording material provided with a protective layer and a heat insulating layer. However, the techniques described in these publications all require vacuum-based equipment for vapor deposition or sputtering, making the recording material produced extremely expensive and the production process complicated.

Furthermore, selenium, tellurium, bismuth, indium, tin,
Or oxides, fluorides, oxides, etc. of these metals,
It has drawbacks such as being unfavorable from a human health standpoint and having a high risk of causing pollution. On the other hand, Japanese Patent Publication No. 51-35144 discloses that a recording layer in which an energy absorbing substance is dispersed in a self-oxidizing binder is provided on a transparent support, and a laser beam is irradiated through the support. There is a description of an image recording method in which the recording layer is blown away.

However, the recording layer produced by this technique is easily damaged, has extremely low film strength, has poor resolution, and has disadvantages such as the recording method requires a large amount of recording energy. Therefore, the inventors of the present invention have completed the present invention as a result of intensive research into a recording method that is inexpensive, has little risk of pollution, and has a strong film strength, and can record with low energy. This is what I did.

Therefore, an object of the present invention is to provide a recording method that allows recording with low energy.

Another object of the present invention is to provide a recording method that can use a recording material with strong film strength.

Furthermore, another object of the present invention is to provide a recording method that can use recording materials that are inexpensive and have little risk of causing pollution.

The above-mentioned objects of the present invention are achieved by a recording method that uses a heat-sensitive recording material in which exposed areas become insolubilized and insolubilizes the exposed areas by irradiation with laser light, which is characterized in that the exposure is carried out through a support.

According to a preferred embodiment of the invention, the heat-sensitive recording material comprises a hydrophobic thermoplastic polymer dispersed in a hydrophilic binder in a ratio of greater than 1:1 with a light-absorbing substance that converts absorbed light into heat. It has a heat-sensitive layer containing coalesced particles, and the binder is a water-soluble polymer compound. In addition, according to another preferred embodiment of the present invention, it is not necessary to use an organic solvent or alkaline aqueous solution as the processing liquid used to remove the unexposed area after exposure (recording), and the binder of the heat-sensitive layer can be removed. using a solvent, especially an aqueous liquid. Another preferred embodiment of the present invention is to use a heat-sensitive recording material having a heat-sensitive layer containing an ionomer resin as hydrophobic thermoplastic polymer particles. Another preferred embodiment of the present invention According to this, the ionomer resin is a copolymer of α-olefin (especially ethylene) and α/β monounsaturated carboxylic acid (especially acrylic acid or methacrylic acid) with metal ions (especially Na+, Mg++, Zn++). It is a crosslinked resin, and the heat-sensitive layer of the present invention contains a water-soluble polymer compound (preferably polyvinyl alcohol, particularly preferably one containing 85 to 90% vinyl alcohol units) as a binder. Furthermore, the ratio of the ionomer resin to the water-soluble polymer compound is 2:3 to 9:1 by weight.

The ionomer resin used in the present invention can be any ionomer resin, but preferably α-
It is a resin made by ionic crosslinking of olefin and α/β monounsaturated carboxylic acid with one or more types of metal ions.

The α-olefin used in the base copolymer of this ionomer resin has the general formula RCH=CH2. Here, R is a hydrogen atom or an alkyl group, and the alkyl group preferably has 1 to 8 carbon atoms. That is, suitable olefins include ethylene, propylene, butene-1, benzene-1, hexene-1, and heptene-1.
3-Methylbutene-1, 4-methylbenzene-
1st prize is included. The α·β monounsaturated carboxylic acid, which is the second component of the copolymer, is preferably an α·β monounsaturated carboxylic acid having 3 to 8 carbon atoms.

That is, preferred α/β monounsaturated carboxylic acids include acrylic acid, methacrylic acid, ethacrylic acid, itaconic acid, maleic acid, fumaric acid, and esters of these carboxylic acids, such as methyl acrylate, ethyl acrylate, methyl methacrylate, and methacrylate. Includes n-butyl acid, dimethyl fumarate, diethyl itaconate, dimethyl maleate, etc. These α-olefins or α·β monounsaturated carboxylic acids may be used singly or in combination of two or more types.

Metal ions suitable for producing an ionomer resin from this copolymer are metal ions having a valence of 1 to 3.

Suitable monovalent metal ions include Na+, K+, Li+,
Cs+, Ag+, Hg+, Be as a divalent metal ion
++, Mg++, Ca++, Sr++, Ba++, Cu
++, Cd++, Hg++, Sn++, Pb++, Fe
++, CO+. +, Ni++, Zn++, A1+++, S as Ξ-valent metal ions. +++, Fe+++, Y+
++ can be mentioned. Among these, in the present invention, Na
+, Mg++ or Zn++ are preferred. Among these ionomer resins, preferred are ethylene and acrylic acid or methacrylic acid combined with Na+, Mg++ or Z
It is an ionomer resin obtained by ionic crosslinking with n++.

Regarding the manufacturing method of the ionomer resin used in the present invention, Japanese Patent Publication No. 39-6810, Japanese Patent Publication No. 42-1576
No. 8, JP-A-49-31556, JP-A-49-121
The method described in each publication such as No. 891 may be followed.

The heat-sensitive recording material used in the invention may contain some binder, in particular a hydrophilic binder.

Preferred hydrophilic binders include, for example, gelatin, glue, casein, zein, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, carboxymethylhydroxyethylcellulose, hydroxyethylstarch, gum arabic, sucrose octaacetate, ammonium alginate, and alginic acid. Examples include soda, polyvinyl alcohol, polyvinylpyrrolidone, polyvinylamine, polyethylene oxide, polystyrene sulfonic acid, and polyacrylic acid. In the present invention, polyvinyl alcohol is preferable, especially with a degree of saponification of 8.
5-90% polyvinyl alcohol is preferred. The heat-sensitive recording material used in the present invention does not necessarily need to contain a binder.

The amount of hydrophilic binder can vary from o% to 80%, but is preferably from 10% to 60%. When the hydrophilic binder content is less than 10%, the solubility of the non-image area is insufficient, and when it exceeds 60%, the strength of the image area may be insufficient. The ionomer resin preferred for the heat-sensitive recording material used in the present invention can be applied by an aqueous dispersion which may contain a hydrophilic binder.

This aqueous dispersion can be obtained by dispersing the ionomer resin in pressurized and heated water. This method is described in detail in Japanese Unexamined Patent Publication No. 51-62890. According to another method, the ionomer resin can be obtained by dispersing a finely ground ionomer resin in water using a surfactant or a hydrophilic protective colloid such as polyvinyl alcohol. The size of the ionomer resin particles in the dispersion may be from 0.01 to 50 microns. Preferably 0.05~
A size of 2μ is good. If the particles are larger than 2μ, the resolution may be reduced, and if the particles are smaller than 0.05μ, the sensitivity may be reduced. The mixing ratio of the ionomer resin used in the present invention and the water-soluble polymer compound (especially polyvinyl alcohol) as a binder is not limited, but is preferably 2:3 to 9:1 by weight.

If the mixing ratio of the ionomer resin is outside this range, that is, if the mixing ratio of the ionomer resin is too low, the strength of the border area may be insufficient, and if it is too large, the solubility of the non-image area may not be sufficient. The ionomer resin used in the present invention is applied as an aqueous dispersion, and the content of the ionomer resin in this aqueous dispersion is 1 to 100% relative to water.
%. If it is less than 1%, a sufficient film thickness will not be obtained when applied, and if it is more than 100%, the viscosity may become high and handling may become difficult.

It is desirable to add pigments and dyes to the heat-sensitive layer used in the present invention in order to effectively utilize high-density energy produced by laser beams such as YAG laser, Ar laser, and He--Ne laser.

The pigment or dye used for this purpose may be any pigment or dye that converts the laser beam pattern into a thermal pattern, but in particular carbon graphite, carbon black, phthalocyanine pigments, iron powder, graphite powder,
Pigments having absorption in the visible and near-infrared regions, such as iron oxide powder, lead oxide, and blackened silver, are preferred, and carbon black is particularly preferably used. When an ionomer resin as a heat-sensitive component and, if necessary, a hydrophilic binder and a pigment (especially carbon black, etc.) or dye are used in the heat-sensitive layer used in the present invention, the combination of the ionomer resin and the binder may be used. The mixing ratio of pigment or dye is 1:1 to 20:1 by weight.
It is desirable that Furthermore, the dye used in the present invention,
The pigment can also be applied by previously dissolving or dispersing it in the ionomer resin. The support for the heat-sensitive recording material used in the present invention is preferably transparent, but slightly opaque or colored supports may also be used.

For example, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate/butyrate, cellulose nitrate, polyethylene terephthalate,
Examples include plastic films such as polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc., or glass plates. Among these supports, polyethylene terephthalate is preferred. In the heat-sensitive recording material used in the present invention, gelatin, casein, polyvinyl alcohol, ethyl cellulose, phenolic resin, diazoresin, styrene-maleic anhydride copolymer, polyacrylic acid, etc. are optionally added between the support and the heat-sensitive layer. An intermediate layer consisting of may be provided for the purpose of improving adhesion between the support and the heat-sensitive layer or preventing pinholes. Further, in order to prevent scratches on the surface of the heat-sensitive layer or improve vacuum adhesion, the heat-sensitive recording material used in the present invention may be provided with an overcoat layer that dissolves or swells during development.

This overcoat layer may be mechanically matted or a resin layer containing a matting agent. Matting agents include silicon dioxide, zinc oxide, titanium oxide, zirconium oxide, glass particles, alumina, starch,
Included are polymeric particles (eg, particles of polymethyl methacrylate, polystyrene, phenolic resins, etc.) and matting agents as described in US Pat. No. 2,701,245 and US Pat. No. 2,992,101.

Two or more of these can be used in combination. The resin used in the overcoat layer containing the matting agent is appropriately selected. Specifically, for example, gum arabic, glue, gelatin, casein, celluloses (e.g., viscose, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, etc.), starches (e.g., soluble starch, modified starch, etc.), polyvinyl alcohol, polyethylene oxide, polyacrylic acid, polyacrylamide, polyvinyl methyl ether, polyvinylpyrrolidone, polyamide, etc. Two or more of these can be used in combination. In order to produce the heat-sensitive recording material used in the present invention, for example, an aqueous ionomer resin dispersion, a hydrophilic binder, and a pigment or dye are mixed, and the mixture is mixed with a ball mill,
Disperse uniformly using an ultrasonic dispersion machine, etc.

The obtained dispersion is coated on the support to a thickness of 1 to 50 μm, preferably 1 to 15 μm, and dried at a temperature of 30 to 50°C. The heat-sensitive recording material used in the present invention can be developed using only an aqueous solution without using an organic solvent or an alkaline aqueous solution.

According to the first method, an image can be obtained by washing away the remaining transparent, soluble portion of the recording material.

According to a second method, an image can be obtained by immersing the recording material in an aqueous dye solution and allowing the dye to diffuse into the areas that remain hydrophilic.

According to a third method, an image can be obtained by transferring the remaining hydrophilic portions of the recording material to an image-receiving material in a wet or dry state. According to a fourth method, a plurality of copies can be obtained by using in lithographic printing a recording material in which a hydrophilicity-hydrophobicity difference is formed according to the image. The high-density energy light used in the present invention includes, for example, Ar laser light, He-Ne laser light,
This is laser light such as semiconductor laser light.

In the method of the present invention, the laser beam may be used for exposure through the support of the heat-sensitive recording material, that is, from the support side. The laser light used in the present invention may be so-called O-order light or may be first-order light.

Applications of the present invention include (1) scanning exposure with laser light;
It has industrial advantages such as being able to be used as a facsimile film or a lithographic master, and (2) producing a high-resolution lithographic film at low cost.

EXAMPLES The present invention will be specifically explained below using Examples, but the embodiments of the present invention are not limited thereby.

Example 1 A composition according to the above weight ratio was dispersed with glass beads for 30 minutes, and was spread onto a polyethylene terephthalate (PET) film having a thickness of 100 μm with a gelatin subbing layer using a wire bar to give a dry weight of about 45 W/d. It was applied so that

This recording material was dried at 50° C. or lower to prepare a sample.
This sample was divided into two parts, and each part was exposed to light using the following method.

That is, this sample was subjected to scanning exposure using a cylindrical external beam scanning type laser scanning exposure machine. The laser light source is manufactured by SpectraPhysics (model 125A).
) of 50mW, . AOM using He-Ne laser light source
(acousto-optic modulation element: manufactured by Matsushita Electronics Co., Ltd.), and the O-order light of the He-Ne laser beam is focused by a 5x lens, on the support side of the recording medium (method of the present invention) and on the recording layer side. (Method for comparison) Exposure and recording.

Next, the two samples were immersed in tap water and the recording layer was rubbed with a sponge, so that the unexposed portions were dissolved and removed. As a result, exposure from the support side according to the method of the present invention resulted in approximately 1
It is possible to record up to a linear velocity of m/Sec, whereas when exposed from the recording layer side using the comparative method, the linear velocity is approximately 40c!
It was found that recording was not possible with RL/Sec.

Therefore, it can be seen that the recording method of the present invention has a recording time that is more than twice as short and requires less recording energy. Example 2 Each of the same samples obtained in Example 1 was subjected to LOgE.
MODEL24l7. manufactured by scan. LaserPld,
Exposure was performed from the support side and the recording layer side using an emalcing system.

At this time, a YAG laser was used as a laser light source, and the laser power was 7.5W and the beam diameter was 30.5μ. As a result, a visible image was obtained before development with both exposure from the support side and the recording layer side.

However, when developed in the same manner as in Example 1, a clear image could be obtained only by the exposure method from the support side. Therefore, it can be seen that the recording method of the present invention is significantly superior to the method of exposing from the recording layer side. Example 3 The sample obtained in Example 1 and a laser mask (manufactured by Scott Graphics Co., Ltd.: A recording body made of ethyl cellulose and carbon graphite, which is identical to the recording body described in Japanese Patent Publication No. 51-35144, was used. The scratch hardness of the recording layer was compared using a Carroll method scratch tester.

As a result, the sample obtained in Example 1 had almost no damage even under a load of 2007, whereas the laser mask had a load of 0.
I was hurt by r.

Claims (1)

[Scope of Claims] 1. A recording method that uses a heat-sensitive recording material in which exposed areas become insolubilized and insolubilizes the exposed areas by irradiating the exposed areas with laser light, the method comprising exposing the exposed areas to laser light through a support. 2. A thermosensitive recording material comprising, on a support, hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder in a ratio of greater than 1:1 with a light-absorbing substance that converts absorbed light into heat. 2. The recording method according to claim 1, further comprising a layer. 3. The recording method according to claim 2, wherein the hydrophobic thermoplastic polymer particles are an ionomer resin. 4. The recording method according to claim 3, wherein the ionomer resin is a resin obtained by ionically crosslinking a copolymer of an α-olefin and an α/β-unsaturated carboxylic acid with metal ions. 5. The recording method according to claim 4, wherein the α-olefin is ethylene. 6. The recording method according to claim 4, wherein the α/β-unsaturated carboxylic acid is acrylic acid or methacrylic acid. 7 The metal ion is Na^+, Mg^+^+ or Zn^
5. The recording method according to claim 4, wherein the recording method is +^+. 8. The recording method according to claim 2 or 3, wherein the hydrophilic binder is a water-soluble polymer compound. 9. The recording method according to claim 8, wherein the water-soluble polymer compound is polyvinyl alcohol. 10. The recording method according to claim 9, wherein the polyvinyl alcohol contains 85 to 90% vinyl alcohol units. 11. The recording method according to claim 8, wherein the ratio of the water-soluble polymer compound to the ionomer resin is 3:2 to 1:9 by weight. 12. The method according to claim 1, wherein the laser beam is a YAG laser beam. 13. The recording method according to claim 1, wherein the laser beam is an Ar laser beam. 14. The recording method according to claim 1, wherein the laser beam is a He-Ne laser beam.