JPS62222888A - Recording medium - Google Patents

Abstract

PURPOSE:To enhance optical density, hue, color developability, resolving power, background whiteness and a contrast characteristic, by providing a porous ink pervious layer and an unporous ink holding layer and together containing an undyeable particle and a high refractive index particle in the ink pervious layer at least with respect to a recording agent. CONSTITUTION:Because recording is performed on an ink pervious layer being a recording side by a recording liquid and a recording image is observed from an ink holding layer being an observation layer, it is necessary that the ink pervious layer has high affinity to the liquid medium in the recording liquid and a low affinity to a recording agent while, because the ink holding layer absorbs and catches the recording liquid temporarily absorbed by the ink pervious layer, it is necessary than that of the ink pervious layer and the affinity to the recording agent is high. In order to obtain recording having high contrast and excellent in image sharpness, resolving power and he, the undyeable particle (thermoplastic or thermosetting org. resin particle) and pigment particle with a refractive index of 1.5 or more contained in the ink pervious layer are used and the mixing wt. ratio of both of them is different corresponding to the refractive index of the particle to be used and the thickness of the ink pervious layer etc. but set to resin particle/pigment particle = 10/1-100/1.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a recording material suitable for a recording method using a recording liquid, such as a felt pen, a fountain pen, a pen plotter, an inkjet recording device, etc. The present invention relates to a recording material suitable for high-quality recording that has excellent absorbency, color properties of recorded images, and whiteness of the substrate.

[Conventional technology]

Conventionally, recording methods using recording liquid, such as felt-tip pens,
Recording materials used for writing with a fountain pen or ballpoint pen, or for recording with a pen plotter or inkjet recording device include general paper such as high-quality paper, pound paper, and writing paper, and coated paper such as art paper and cast coated paper. Can be mentioned.

However, in recent years, with the development of recording devices such as inkjet recording devices and pen plotters, sufficient recording characteristics have not been obtained with the above-mentioned conventional recording materials.

In other words, because high-speed recording and multicolor recording are performed that are incomparable to conventional recording materials, conventional recording materials have poor absorption of recording liquid, color development when multiple recording liquids land on the same location, Color properties, etc. have not reached a satisfactory level.

In order to solve these problems, coated papers such as inkjet paper having a porous ink absorbing layer on the surface of the base material have been devised.

For example, JP-A-58-136480 describes an inkjet recording medium in which a support (2) is provided with an ink-receiving layer mainly composed of a pigment having a refractive index of 1.58 or less.

Unlike conventional recording media, this recording medium allows the recorded image to be observed from the support side, and the ink-receiving layer adjacent to the support is coated with a pigment having a refractive index of 1.58 degrees or higher. - By configuring it as an L body, it is intended to obtain a recorded image with good color IRF development properties and color density.

However, although this recording medium has relatively good ink absorption, since the pigment layer is used as an ink absorption and retention layer,
It has drawbacks such as poor ink fixability and poor resolution, color, and optical density of recorded images.

In addition, recently, as the speed and quality of recording using inkjet recording devices, pen plotters, etc. has increased,
Recording materials are also required to have dramatic recording performance.

In other words, there is a need for a recording material that is significantly superior to conventional recording materials in all aspects of recording performance, such as absorption of the recording liquid, color development of the recording agent, quality of the recorded image, resolution, color, density of the recorded image, and gloss. It's here.

[Problem that the invention seeks to solve]

However, the current situation is that a recording material that simultaneously satisfies all of these recording properties has not yet been obtained.

Therefore, an object of the present invention is to provide a recording material that has excellent ink absorption and fixing properties.

Another object of the present invention is to provide a recording material from which a recorded image can be obtained that has a high optical density and is excellent in color property, color development, resolution, whiteness of the substrate, and contrast.

A further object of the present invention is to provide a recording material that has a glossy surface and provides recorded images with excellent durability such as water resistance and light resistance.

[Means for solving problems]

The objects set forth in item L are achieved by the present invention as follows.

That is, the present invention has a porous ink-permeable layer and a non-porous ink-retaining layer, and the ink-permeable layer also contains at least particles that are non-stainable to the recording agent and particles with a high refractive index. This is a recording material characterized by:

[Effect]

The first feature of the recording material of the present invention is that, unlike conventional recording materials in which the image recording surface and the observation surface are the same, the image recording surface and the observation surface are in a front-back relationship, Second, in the ink permeable layer, particles that do not stain the recording agent and particles with a high refractive index are used in combination.

That is, in the recording material of the present invention, recording is performed using a recording liquid on the ink permeable layer on the recording side, and the recorded image is observed from the ink retaining layer (or base material) on the observation side.

Therefore, the ink permeable layer has liquid permeability and has the function of quickly absorbing and transmitting the recording liquid attached to its surface.
On the other hand, the ink retaining layer has a function of absorbing and retaining the recording liquid or recording agent transferred from the ink permeable layer.

At this time, the ink permeable layer must have high affinity for the liquid medium in the recording liquid, and at the same time, the recording agent (dye,
On the contrary, it must have a low affinity for colorants such as pigments and color-forming materials 'N).

Therefore, the ink permeable layer wets the recording liquid medium.
It has properties such as penetration and diffusion, and has adsorption and adsorption properties for recording media.
It must be constructed by selecting a material that does not have characteristics such as penetration and reaction.

If the ink permeable layer does not have properties such as wetting, permeation, and diffusion with respect to the recording liquid medium, when the recording liquid is applied to the surface of the ink permeable layer, it will quickly permeate inside the ink permeable layer. As a result, the absorbency of the recording liquid decreases.

Furthermore, the recording liquid remains retained in the ink permeable layer and does not reach the ink retaining layer, making it impossible to obtain a recorded image with excellent water resistance.

Furthermore, if the ink permeable layer has properties such as adsorption, penetration, and reaction with respect to the recording agent, the recording agent will remain on the surface or inside the ink permeable layer and will not reach the ink retaining layer. It becomes impossible to obtain a recorded image with high optical density and sufficient color properties.

On the other hand, the ink retaining layer is only temporarily an ink permeable layer.

Therefore, the ink retaining layer must have high affinity for the recording agent as well as for the recording liquid medium.

As a result of extensive research, the present inventors have found that, in the recording material having the above-mentioned ink permeable layer and ink retaining layer, by making the ink permeable layer contain at least non-staining particles and high refractive index particles, recording is possible. It was discovered that the opacity of the base surface is improved, the contrast of the recorded image is high, and it is possible to provide a recorded image with excellent image clarity, resolution, and color properties, and the present invention was achieved.

Hereinafter, the present invention will be described in detail based on embodiments.

The recording material of the present invention includes a base material as a support, and absorbs substantially the recording liquid or recording agent formed on the support.
The recording medium is composed of an ink retaining layer that captures the ink, and an ink permeable layer formed on the ink retaining layer that directly receives the recording liquid but has liquid permeability that does not substantially leave the recording agent behind.

However, if the ink permeable layer or the ink retaining layer also functions as a base material, the base material is not necessarily required.

As the base material used in the present invention, any conventionally known base material can be used, such as polyester resin, diacetate resin, triacetate resin, polystyrene resin, polyethylene resin, polycarbonate resin, polymethacrylate resin, cellophane, celluloid, polychloride resin, etc. vinyl resin,
Examples include plastic films, plates, and glass plates made of polyimide resin, polysulfone resin, and the like.

As mentioned above, since the recording material of the present invention is to be observed from the side opposite to the recording surface, the base material needs to have light-transmitting properties.

In addition, the base material used may be subjected to any processing as long as it finally has translucency; for example,
It is possible to give the base material a desired pattern or luster (moderate gloss or silky texture).

Furthermore, by selecting a base material having water resistance, abrasion resistance, and blocking resistance, water resistance, abrasion resistance, and blocking resistance can be imparted to the image observation surface of the recording material.

The ink permeable layer constituting the recording material of the present invention needs to have liquid permeability.

In the present invention, liquid permeability means that the recording liquid can pass through quickly,
This is a property that substantially prevents the recording agent in the recording liquid from remaining in the ink permeable layer.

In the present invention, a preferable embodiment for improving liquid permeability is that cracks and communication holes are formed on the surface and inside of the ink permeable layer.
The aim is to create a porous structure containing microscopic particles (including micro-sized ones).

For example, when recording using water-based ink, the following aspects may be mentioned.

(1) An embodiment in which the layer is made up of non-staining particles and a binder and has cracks inside; (2) The layer is made porous by dispersing other materials in the coating and treating it with a solvent. (3) A mode in which the resin is dispersed in a mixed solvent, and the high boiling point solvent acts as a poor solvent for the resin and makes the inside of the layer porous; (4) A mode in which a foaming material is included during removal. , an embodiment in which the inside of the layer is porous.

The materials used at this time are selected to be non-swellable to water and the solvent in the ink, and non-stainable to the dye in the ink.

A preferred embodiment of the ink-permeable layer according to the present invention that satisfies the above-mentioned recording properties is, for example, an embodiment consisting of particles that are non-stainable to the recording agent and a binder.

Examples of non-dyeable particles satisfying the properties described in 1-1 include organic resin particles such as thermoplastic resins and thermosetting resins, such as polyethylene, polymethacrylate, elastomers, ethylene-vinyl acetate polymers, styrene-acrylic polymers, etc. polymer,
At least one of organic resin powders and emulsions such as polyester, polyacrylic, and polyvinyl ether may be used as desired.

However, since the refractive index of these resin particles is 1.3 to 1.6 degrees, sufficient opacity may not be obtained with the resin particles alone, which is not sufficient to obtain high contrast images. .

Therefore, in the present invention, by using particles having a high refractive index, such as pigment particles, the opacity is improved and an image with high contrast is obtained.

Any high refractive index particles having a refractive index of 1.5 or more can be suitably used.

For example, zinc white (refractive index n -1, 9 to 2.0), titanium oxide (n = 2.5 to 2.9), lead white (n = 1.9
~2.1), cadmium yellow (n = 2.2~2.
3), yellow iron oxide (n=2.0), ceracola (n=1.
52 to 1.53), barium sulfate (n=1.63), etc., is used as desired.

The mixing ratio (weight ratio) of the resin particles and pigment particles varies depending on the refractive index of the particles used, the thickness of the ink permeable layer, etc., but generally resin particles/pigment particles = 1/1 to 100/
1, more preferably 10/1 to 100/1.

If this ratio is less than 1/1, the recording agent will be dyed onto the surface of the pigment particles and will not penetrate into the ink retaining layer, making it impossible to obtain sufficient image density.

Further, when this ratio is 100/1 or more, the effect of the pigment particles is not sufficient, and only a recording material with low opacity can be obtained.

The binder used needs to have the same properties and/or properties as the particles described above.

Preferred materials for the binder include any conventionally known materials having the above-mentioned functions, such as polyvinyl alcohol, acrylic resin, styrene-acrylic copolymer, ethylene-vinyl acetate polymer, starch,
One or more of the following resins: polyvinyl butyralmer, gum arabic, carboxymethyl cellulose, polyvinyl pyrrolidone, polyacrylamide, phenol, melamine, epoxy, styrene-butadiene rubber, urea, α-olefin, vinyl urethane, polyurethane, nitrile rubber, chlorobrene, etc. Used as desired.

Furthermore, in order to improve the function as an ink permeable layer, various additives such as surfactants, penetrants, etc. may be added to the ink permeable layer as necessary.

The mixing ratio (weight ratio) of the particles and the binder is preferably in the range of particles/binder = 1/3 to 50/1, more preferably in the range of 3/1 to 20/1. .

If this mixing ratio is 1/3 or less, the cracks and communication pores in the ink permeable layer become small, and the recording liquid absorption effect decreases. Furthermore, if the mixing ratio is 50/l or more, the adhesion between the particles or between the particles and the ink retaining layer becomes insufficient, making it impossible to form an ink permeable layer.

The thickness of the ink permeable layer depends on the amount of recording liquid, but is preferably 1 to 200 Bm, more preferably 5 to 1 Bm.
00p, m.

Next, the non-porous ink retaining layer that substantially captures the recording liquid or recording agent absorbs and captures the recording agent that has passed through the ink permeable layer, and substantially permanently retains the recording agent. Therefore, the ink retaining layer is required to have a stronger ability to absorb recording liquid than the ink permeable layer.

This is because when the absorption power of the ink retention layer is weaker than the absorption power of the ink transmission layer, the recording liquid applied to the surface of the ink transmission layer passes through the ink transmission layer, and the recording liquid is absorbed by the ink transmission layer. When the tip reaches the ink holding layer, the recording liquid will stay in the ink permeable layer, and at the interface between the ink permeable layer and the ink holding layer, the recording liquid will permeate laterally within the ink permeable layer.
It will continue to spread.

As a result, the resolution of the recorded image decreases, making it impossible to form a high-quality image.

Further, as described above, since the recorded image is observed from the side opposite to the recording surface, the ink retaining layer needs to be light-transmissive.

The ink retaining layer that satisfies the above requirements is preferably made of a light-transparent resin that adsorbs the recording agent and/or a light-transparent resin that is soluble and swellable in the recording liquid.

For example, when an aqueous recording liquid containing an acid dye or a direct dye is used as a recording agent, the ink retaining layer has a cationic resin that has an adsorption property for the dye and/or a swellability for the aqueous recording liquid. It will be composed of a hydrophilic polymer.

As the polymer of L, for example, those exemplified below are suitably used.

(1) Block copolymer or graft copolymer having a hydrophilic segment and a hydrophobic segment in the molecule Such a block copolymer or graft copolymer is totally water-insoluble but wood-philic. The wood-philic segments of such polymers include, for example, carboxyl groups, sulfonic acid groups, hydroxyl groups, ether groups, acid amide groups, methylolated groups thereof, primary to tertiary amine groups, quaternary ammonium groups, etc. It is a segment in which two or more vinyl monomers having a hydrophilic group are polymerized. Examples of such wood-philic monomers include (meth)acrylic acid,
Mono (meth)acrylate or monomaleate of polyols such as maleic anhydride, vinyl sulfonic acid, sulfonated styrene, vinyl acetate, ethylene glycol, (meth)acrylic amide, methylolated products thereof, mono- or dialkylaminoethyl (meth)acrylate, Examples include quaternized products of these, vinylpyrrolidone, vinylpyridine, and the like.

Hydrophobic polymer segments include olefins such as ethylene, propylene, and butylene; aromatic vinyl compounds such as styrene, methylstyrene, and vinylnaphthalene; halogenated olefins such as vinyl chloride, vinylidene chloride, and vinylidene fluoride; It is a polymer of two or more heptamers such as acrylic acid, crotonic acid, and various alcohol esters of underground saturated carboxylic acids.

In addition, water-soluble polymers other than those mentioned above, such as albumin,
Gelatin, casein, starch, cationic starch, gum arabic, natural resins such as sodium alginate, polyvinyl alcohol, polyamide, polyacrylamide, polyvinylpyrrolidone, polyethyleneimine, polyvinylpyridylium halide, melamine resin, polyurethane,
Naturally, hydrophilic natural or synthetic polymers such as polyester, sodium polyacrylate, etc., or hydrophobic natural or synthetic polymers modified to be water-insoluble can also be used as the hydrophilic polymer segment or the hydrophobic polymer segment. be.

(2) Crosslinked products of water-soluble polymers Various water-soluble polymers as described above and below are cross-linked with a suitable cross-linking agent or radiation to such an extent that they become water-insoluble without losing their wood-philicity.

(3) Polymer complex A polymer complex is a mixture of two or more water-soluble to wood-philic polymers that are different from each other and act on each other, and have properties different from any of the original polymers. For example, two or more types of polymers form some kind of strong bond due to interionic electrostatic force, hydrogen bonding, van der Waals force, partial transfer of charge, etc.

Although various kinds of polymer complexes can be used, a particularly preferred one in the present invention is a polymer complex consisting of a basic polymer and an acidic polymer.

Note that the material constituting the ink retaining layer is not particularly limited as long as it has the function of absorbing and trapping the recording liquid and can form a non-porous layer.

The thickness of the ink holding layer may be sufficient as long as it is sufficient to absorb and trap the recording liquid, and although it varies depending on the speed of the recording liquid, it is preferably 1 to 50 Bm, more preferably 5 to 1100 Bm.
It is pL.

The method for forming the ink retaining layer and the ink permeable layer on the base material is to prepare a coating solution by dissolving or dispersing it in an appropriate solvent as described in 2. By known methods such as bar coating method, spray coating method, air knife coating method, etc.
It is preferable to apply the coating onto a coating material and then dry it as described above, using the hot-melt coating method described above, or by forming a single sheet from the above-mentioned materials and then laminating the sheet onto a base material. You can also do something like this.

However, when providing the ink retaining layer on the Omura, it is necessary to strengthen the adhesion between the base material and the ink retaining layer and eliminate spaces.

If a space exists between the base material and the ink retaining layer, the surface of the recorded image will be subject to diffuse reflection, which will reduce the substantial optical density of the image, which is not preferable.

Examples of means for forming an image using the recording material of the present invention include a fountain pen, a ballpoint pen, a felt-tip pen, and a pen plotter.
, ink mist, inkjet, various types of printing, and other recording devices and devices that use a recording liquid containing a recording agent.

Among these recording devices and recording devices, inkjet recording devices and pen plotters are preferred from the viewpoint of high-speed image recording.

The recording liquid for recording on the recording material of the present invention includes:
Conventionally known aqueous and/or pongee yarn recording liquids are preferred, and in order to quickly penetrate into the ink permeable layer and be quickly absorbed and captured by the ink retaining layer, the viscosity of the recording liquid should be 100.
ps or less, preferably 100 cps or less, preferably 50 cps or less
It is necessary that it is less than cps.

Further, in consideration of stability against fire, resistance to environmental contamination, etc., a water-based recording liquid is preferable. As the recording agent contained in the recording liquid, any conventionally known coloring agents such as dyes and pigments and/or those having color-developing properties can be used.

For example, as the recording agent used in inkjet recording, water-soluble dyes such as direct dyes, acid dyes, basic dyes, reactive dyes, and food colorants are preferred.

Formation of an image using the recording material of the present invention is carried out by recording an image with a recording liquid on the ink-permeable layer side of the recording material using a recording device capable of printing mirror characters (reverse characters). .

〔Example〕

Hereinafter, the present invention will be specifically explained based on Examples. still,
In the text, unless otherwise specified, parts are by weight.

Examples and Comparative Examples - A polyethylene terephthalate film (thickness 100 g, m: manufactured by Toshi) was used as a translucent base material, and the following composition A was coated on top of the film with a bar so that the dry film thickness was 8 gm. It was coated by a coater method and dried in a drying oven at 120°C for 5 minutes.

Further, compositions B to F of f are coated on the composition A by a bar coater method under the conditions described above, and dried in a drying oven to produce recording materials 1 to 5 of the present invention. did.

Composition B (Insect-friendly material 1) Dry film thickness 20 pm, 70°C, drying in separate volumes Composition C
(Browning material 2) Dry film thickness 20 pLm, 80°C, 20Jm drying> Composition D (Browning material 3) Dry film thickness 20 lm, 80°C, 20Jm drying> Composition E
(Medium material 4) Dry film thickness 20#1. For comparison, compositions B to D of recording materials 1 to 3 were used for comparison. Recording materials 6 to 8 did not contain barium sulfate, titanium oxide, or zinc white, respectively.

All of the eight recording materials thus obtained were white and opaque.

For these recording materials, we use a recording device with an on-demand inkjet recording head that uses the following four types of ink to generate bubbles with a heat-generating resistor and uses the pressure to eject recording liquid. Inkjet recording was performed in solid color.

Table 1 shows the compositions of the four types of recording liquids used.

Table 1 Yellow ink C, 1, Direct Yellow 86
2parts N-methyl-2-pyrrolidone
10 parts diethylene gelcol
20 parts polyethylene glycol #200 15fl
i'll water
55 parts magenta ink C, 1, acid red 35
2parts N-methyl-2-pyrrolidone
io part Kujiethylene gelcol
20 parts polyethylene glycol #200 15 parts water
55 parts cyan ink C, 1, direct blue 86
2parts N-methyl-2-pyrrolidone
io part Kujiethylene gelcol
20 parts polyethylene glycol #200 15 parts water
55 parts black ink C, 1, food black 2
2parts N-methyl-2-pyrrolidone
10 parts diethylene gelcol
2o parts polyethylene glycol 9200 15 parts water
55 copies of the thus obtained recorded material was tested and evaluated in accordance with the following method to determine whether it was sufficiently suitable for the purpose of the present invention. The results are shown in Table 2.

l) Ink absorption was measured by leaving the recorded matter at room temperature after inkjet recording, and measuring the time until the ink was sufficiently dried and fixed without adhering to the recorded area even when touched with a finger.

2) Image optical density (0, D) is determined by Macbeth densitometer TR-
524, image observation surface A for the black ink recording area.
was measured from recording surface B.

3) To determine the dot shape, observe the printed dots with a stereomicroscope. If the dot is slightly round, mark it as 0. If the circle is slightly distorted, mark it as Δ.
An amorphous object was designated as X.

4) Whiteness was measured using a new digital hunter reflectance meter manufactured by Toyo Seiki.

5) Color clarity was determined by visually comparing the color clarity of the inkjet recorded images, and ranking the best as 0, the worst as ×, and rank ■, ○, Δ, and ×.

Table 2 [Effects] The recording material of the present invention configured as described above has advantages that can be obtained conventionally by observing the recorded image from the side opposite to the recording surface, that is, from the ink retaining layer or the base material side. It has excellent effects that have never been seen before. In other words, because the ink retaining layer has light transparency, diffuse reflection on the image viewing surface side is reduced, and a high image optical density that cannot be achieved when recording on paper etc. can be obtained, as well as gloss and water resistance. sex,
Provides weather resistance and abrasion resistance. In addition, the ink-permeable layer that serves as the recording surface has liquid permeability and includes crack communication holes, which improves the absorption of the recording liquid and the resolution of the recorded image, making it possible to provide a clear recorded image. .

Furthermore, by configuring the particles in the ink-permeable layer with particles that do not stain the recording material and particles with a high refractive index, ink permeability can be maintained at a level sufficient for practical use and the ink-permeable layer can be free of stains. It improves transparency and allows you to obtain clear images with high contrast.

As described above, the present invention has excellent effects on recording liquid absorption, sharpness of recorded images, optical density, resolution, gloss, water resistance, weather resistance, and abrasion resistance.

Claims (8)

[Claims] (1) It has a porous ink-permeable layer and a non-porous ink-retaining layer, and the ink-permeable layer has at least particles that are non-stainable to the recording agent and particles with a high refractive index. recording material. (2) Claim 1, wherein the mixing ratio (weight ratio) of the non-staining particles and the high refractive index particles is from 1/1 to 100/1.
Recording material described in section. (3) The recording material according to claim 1, wherein the mixing ratio (weight ratio) of the non-staining particles and the high refractive index particles is from 10/1 to 100/1. (4) The recording material according to claim 1, wherein the ink retaining layer and the ink permeable layer are laminated on a base material. (5) The recording material according to claim 4, wherein the base material is translucent. (6) The recording material according to claim 1, wherein the non-stainable particles are resin particles. (7) The recording material according to claim 1, wherein the high refractive index particles are pigment particles. (8) The recording material according to claim 1, wherein the high refractive index particles have a refractive index of 1.5 or more.