JPS62280069A - Recording material - Google Patents

Abstract

PURPOSE:To obtain a recording material showing high contrast between a recorded area and a nonrecorded area and having excellent color properties, by providing an ink transport layer and an ink-holding layer, and incorporating a fluorescent brightener in the ink transport layer. CONSTITUTION:A recording material comprises a base as a support, an ink- holding layer provided on the support to absorb or trap a recording liquid or a recording agent, and an ink transport layer provided on the ink-holding layer to directly the recording liquid but have a liquid-passing property so that the recording agent can not remain therein. A fluorescent brightener is incorporated in the ink transport layer, whereby images can be recorded with high contrast and excellent resolution and color properties. The ink transport layer comprises nonporous particles non-dyeable with the recording agent and a binder. The nonporous particles may be particles of an organic resin such as a thermoplastic resin and a thermosetting resin or an inorganic pigment. The binder may be polyvinyl alcohol, an acrylic resin, a styrene-acryl copolymer or the like. As the fluorescent brightener, C.I. fluorescent brightening agent is used.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Industrial Application Fields] The present invention relates to a felt pen, a fountain pen, a pen plotter, an inkjet recording device, etc., which are suitable for recording methods using recording liquid. The present invention relates to a recording material, particularly a recording material suitable for high-quality recording that has excellent recording liquid absorption properties and color properties of recorded images.

[Prior Art] 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 are attached to 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 an ink-receiving layer mainly composed of a pigment having a refractive index of 1.58 or less is provided on a support.

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 made mainly of pigments with a refractive index of 1.58 or less. By configuring it as such, it is possible to obtain a recorded image with good color reproducibility and color density.

However, although this recording medium has relatively good ink absorption, since the pigment layer is used as an ink absorption/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 recording materials that are significantly superior to conventional recording materials in all aspects of recording performance, such as absorption of recording liquid, color development of recording agents, quality of recorded images, resolution, color, density of recorded images, and gloss. It has become.

[Problems to be Solved by the Invention] However, the current situation is that a recording material that simultaneously satisfies all of these recording characteristics has not yet been obtained.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a recording material with high contrast between recorded areas and non-recorded areas and excellent color properties.

Another object of the present invention is to provide a recording material from which recorded images with high optical density, excellent color development, and resolution can be obtained.

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 above object is achieved by the present invention as follows.

That is, the present invention is a recording material characterized in that it has an ink transport layer and an ink retention layer, and the ink transport layer contains a fluorescent whitening agent.

[Function] The main feature of the recording material of the present invention is that it has an ink transport layer and an ink retention layer.

That is, in the recording material of the present invention, when recording is performed using a recording liquid on the ink transporting layer, which is the ink applying side, and the recorded image is observed from the ink retaining layer side, an image having a very high optical density is obtained. can get.

Therefore, the ink transport 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 holding layer has liquid permeability, and has the function of quickly absorbing and transmitting the recording liquid attached to its surface. It has the function of absorbing and retaining agents.

At this time, the ink transport layer must have high affinity for the liquid medium in the recording liquid, and at the same time, the recording agent (dye,
For colorants such as pigments and materials with color-forming properties,
On the contrary, affinity must be low.

Therefore, the ink transport layer wets and 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 transport 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 transport layer, it will quickly penetrate into the ink transport layer. As a result, the absorbency of the recording liquid decreases.

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

If the ink transport layer has properties such as adsorption, penetration, or reaction to the recording agent, the recording agent will remain on the surface or inside the ink transport layer and will not reach the ink retention layer. , it becomes impossible to obtain a recorded image with high optical density and sufficient color properties.

On the other hand, since the ink retaining layer absorbs and captures the recording liquid temporarily absorbed by the ink transport layer, it must have a stronger ability to absorb the recording liquid than the ink transport 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 intensive research, the present inventors have discovered that the above-mentioned recording material has an ink transport layer and an ink retention layer, and that the ink transport layer described above can be improved by containing a fluorescent whitening agent in the ink transport layer. The inventors discovered that it is possible to provide recorded images with high contrast, excellent resolution, and color properties without deteriorating functionality, leading to the present invention.

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 base material is not necessarily required when the base material has the functions of an ink retaining layer for capturing and directly receiving the recording liquid formed on the ink retaining layer.

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.

In addition, in the recording material of the present invention, when the recorded image is observed from the side opposite to the ink-applied 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 ultimately has translucency (for example,
It is possible to give the base material a desired pattern or luster (moderate gloss or grain pattern).

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 transport layer constituting the recording material of the present invention needs to have liquid permeability.

The term "liquid permeability" as used in the present invention refers to the property of allowing the recording liquid to pass quickly through the ink transport layer and not substantially leaving the recording agent in the recording liquid in the ink transport layer.

In the present invention, a preferable embodiment for improving liquid permeability is to have cracks and communication holes on the surface and inside of the ink transport 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 composed of non-porous particles and a binder and has internal cracks; (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 foamable material is included during film formation; A mode 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 transport layer according to the present invention that satisfies the above properties is, for example, an embodiment comprising non-porous particles that are non-stainable to recording materials and a binder.

Non-porous particles satisfying the above properties include organic resin particles such as thermoplastic resins and thermosetting resins, such as polyethylene, polymethacrylate, elastomers, ethylene-vinyl acetate polymers, styrene-acrylic copolymers, At least one of organic resin powders and emulsions such as polyester, polyacrylic, and polyvinyl ether, and non-porous inorganic pigment powders may be used as desired.

Furthermore, the binder used has the function of binding the particles and/or the ink retaining layer, and, like the particles, must be non-adsorbent to the recording material. .

As a material preferable as a binder, any conventionally known material can be used as long as it has the above-mentioned function. For example,
Polyvinyl alcohol, acrylic resin, styrene-acrylic copolymer, ethylene-vinyl acetate polymer, starch, polyvinyl butyral, gelatin, casein, ionomer, gum arabic, carboxymethyl cellulose,
Polyvinylpyrrolidone, polyacrylamide, phenol, melamine, epoxy, styrene-butadiene rubber,
One or more resins such as urea, α-olefin, vinyl urethane, vinyl acetate, chloroprene, and nitrile rubber may be used as desired.

As the fluorescent brightener used in the present invention, the following can be exemplified. That is, C,1,fluorescent brightening agent (C91,F]uor
essent Brightening Agen
t) 14, 22, 24, 30, 32, 37
, 45, 52, 54, 55, 56, 84,
85, 86, 87, 90, 91, 92, 104, 112, 1211 134, 135, 153, 162, 163, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, etc.

Examples of methods for incorporating a fluorescent brightener into the ink transport layer include adding it to the coating solution when coating the ink transport layer, or adding it by immersing it in a fluorescent brightener solution after forming the ink transport layer. Although there are several methods, any method may be used as long as it can uniformly contain the fluorescent brightener in the ink transport layer.

The amount of fluorescent brightener contained in the ink transport layer is 0.00% based on the weight of particles constituting the ink transport layer.
A suitable range is 1 to 5% by weight, preferably 0.005% by weight.
-3% by weight, more preferably 0.007-2%. If the content is less than 0.001% by weight, the action of the fluorescent whitening agent will not appear, which is not preferable. Further, if the content is 5% by weight or more, the liquid permeability of the ink transport layer is inhibited and a sufficient image cannot be formed.

Furthermore, in order to improve the function as an ink transport layer, various additives may be added to the ink transport layer as necessary.

Furthermore, conventionally known inorganic pigments may be added to the extent that they do not impede the liquid permeability of the ink transport layer.

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

When this mixing ratio is 1/3 or less, cracks and communication pores in the surface layer become small, and the recording liquid absorption effect decreases. Furthermore, if the mixing ratio is 50/1 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 transport layer.

The thickness of the ink transport layer depends on the appropriate amount of recording liquid, but is preferably 1 to 200 μm, more preferably 3 to 80 μm.
It is μm.

Next, the non-porous ink holding layer that substantially captures the recording liquid or recording agent absorbs and captures the recording liquid that has passed through the ink transport layer, and substantially permanently retains the recording liquid.

Therefore, the ink retaining layer is required to have a stronger ability to absorb recording liquid than the ink transport layer.

This is because if the absorption power of the ink retention layer is weaker than the absorption power of the ink transport layer, the recording liquid applied to the surface of the ink transport layer will pass through the ink transport layer, and the leading edge of the recording liquid will pass through the ink transport layer. When the recording liquid reaches the holding layer, the recording liquid stays in the ink transport layer, and at the interface between the ink transport layer and the ink holding layer, the recording liquid permeates and diffuses laterally within the ink transport layer. becomes.

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

Furthermore, when observing the recorded image from the side opposite to the ink-applied surface, the ink-retaining layer needs to be light-transmissive.

The ink retaining layer that satisfies the above requirements is preferably composed 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 above-mentioned polymer, those illustrated below are preferably used.

(1) Block copolymers or graft copolymers having a hydrophilic segment and a hydrophobic segment in the molecule These block copolymers or graft copolymers are generally water-insoluble but hydrophilic. Hydrophilic 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 amino 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 hydrophilic monomers include (meth)acrylic acid,
Mono(meth)acrylates or monomalates of polyols such as maleic anhydride, vinyl sulfonic acid, sulfonated styrene, vinyl acetate, and ethylene glycol;
(meth)acrylic acid amide and their methylolated products,
Examples include mono- or dialkylaminoethyl (meth)acrylate, quaternized products thereof, 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 monomers 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, polyvinylpyricillium halide, melamine resin, polyurethane, polyester, sodium polyacrylate It goes without saying that hydrophilic natural or synthetic polymers such as the above 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.

(2) Crosslinked water-soluble polymers Various water-soluble polymers as described above and below are crosslinked with a suitable crosslinking agent or radiation to the extent that they become water-insoluble without losing their hydrophilicity.

(3) Polymer complex A polymer complex is made up of two or more water-soluble to hydrophilic polymers that are different from each other and that act on each other, and it produces a mixture with 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 (although it varies depending on the amount of recording droplets, it is preferably 1 to 50 μm, more preferably 3 to 20 μm).
It is m.

As a method for forming an ink retaining layer and an ink transport layer on a base material, a coating solution is prepared by dissolving or dispersing it in the above-mentioned appropriate solvent, and the coating solution is coated by, for example, a roll coating method,
Rod bar coating method, spray coating method,
It is preferable to apply the coating onto the substrate by a known method such as the air knife coating method and then dry it as described above. Alternatively, a method such as laminating the sheet onto a base material may be used.

However, when providing the ink retaining layer on the base material, it is necessary to ensure strong 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, it is not preferable because the surface of the recorded image will be subject to diffuse reflection and the substantial optical density of the image will be lowered.

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 semi-based 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 recording liquid should have a viscosity of 1000c.
ps or less, preferably 1oOcps or less, preferably 50
It must be 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 dye, pigment coloring agent, and/or coloring agent 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 colorings are preferred.

In order to form an image using the recording material of the present invention, in addition to a general recording device and a writing instrument, a recording device capable of printing mirror characters (inverted characters) is used to form an image on the ink transport layer side of the recording material. ,
This is done by recording an image using a recording liquid.

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

Example 1 A polyethylene terephthalate film (thickness: 100 μm, manufactured by Toshi ■) was used as a translucent base material, and the following composition A was coated onto this base material using a bar coater method to a dry film thickness of 10 μm. , 110'C, 10 minutes in a drying oven.

Composition A Further, Composition B below was coated thereon by a bar coater method to a dry film thickness of 15 μm, and dried in a drying oven at 70° C. for 10 minutes.

Composition B The recording material thus obtained was white and opaque. The following four types of ink are used on this recording material using a recording device that has an on-demand inkjet recording head that generates bubbles with a heating resistor and uses the pressure to eject recording liquid. Inkjet recording was performed.

Table 1 shows the compositions of the four types of recording liquids used. The recorded matter thus obtained was tested and evaluated in accordance with the following method to determine whether it was sufficiently suitable for the purpose of the present invention.

(1) 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 finger even if the recorded area was touched with the finger.

(2) Image optical density (0, D) is Macbeth densitometer TR.

524, the black ink recorded area was measured from the image viewing surface side.

(3) To determine the shape of the dots, observe the printed dots with a stereomicroscope.
, Irregular shapes were marked as ×.

(4) Color clarity was determined by visually comparing the color clarity and high contrast of the inkjet recorded images, and ranking the best one as ◎, the worst as ×, and ranked ◎, ○, △, and ×. .

Table-1 Yellow ink (composition) C, 1, Direct Yellow 86 2 parts Polyethylene glycol #200 15 parts Water
55 parts Magenta ink (composition) C0I, Acid Red 35 2 parts Polyethylene glycol #200 15 parts Water
55 parts Cyan ink (composition) C, 1, Direct Blue 86 2 parts Polyethylene glycol #200 15 parts Water
55 parts Black ink (composition) C, 1, Food black 2 2 parts polyethylene glycol @ 200 15 parts water
55 parts Example 2 Using the polyethylene terephthalate film used in Example 1 as a translucent base material, Composition A used in Example 1 was coated on this base material by a bar coater method to a dry film thickness of 10 μm. It was coated and dried in a drying oven at 110°C for 10 minutes.

Furthermore, the following composition C was coated thereon by a bar coater method to a dry film thickness of 15 μm, and dried in a drying oven at 80° C. for 10 minutes.

The recording material obtained from the composition was white and opaque. Inkjet recording similar to that in Example 1 was performed on this recording material.

Further, the recording material was evaluated according to the method of Example 1. The above results are shown in Table-2.

Example 3 Using the polyethylene terephthalate film used in Example 1 as a translucent base material, composition A used in Example 1 was coated onto this base material using a bar coater method so that the dry film thickness was 10 μm. It was then dried in a drying oven at 110°C for 10 minutes.

Further, the following composition was coated thereon by a bar coater method to a dry film thickness of 15 μm, and dried in a drying oven at 80° C. for 10 minutes.

Composition D The recording material thus obtained was white and opaque. Inkjet recording similar to that in Example 1 was performed on this recording material.

Further, the recording material was evaluated according to the method of Example 1. The above results are shown in Table-2.

Comparative Examples 1 to 3 White opaque recording materials were obtained in the same manner as in Examples 1 to 3 except that no fluorescent whitening agent was contained.

Inkjet recording similar to that in Example 1 was performed on these recording materials and evaluated.

The above results are shown in Table-2.

Table-2 Ink absorption Image optical density Dot shape Color clarity B Example 1 2 seconds 1.86 0.58
△ ◎2 2 seconds 1.79 0.63
0 ◎3 1 second 1.85 0.60
0 ◎Comparative example 1 3 seconds 1.86 0
．． 55 △ △2 2 seconds 1.7
9 0.59 Q △3 2 seconds 1
．． 85 0.58 0 Δ [Effects of the Invention] As described above, in the recording material of the present invention, it is possible to observe an image from the ink-applied surface by heating and making the ink transport layer transparent. The application surface and the observation surface are in a front-back relationship, that is, recording is performed from the ink transport layer side,
By observing from the base material side (or the ink retaining layer side), it is possible to produce clear recorded images with extremely high optical density, which was previously impossible when recording on porous sheets such as paper. can be provided.

Furthermore, the recording material of the present invention has an extremely high image contrast due to the inclusion of a fluorescent whitening agent in the ink transport layer, and can provide an image with excellent color clarity.

Claims (5)

[Claims] (1) A recording material comprising an ink transport layer and an ink retention layer, and the ink transport layer contains a fluorescent whitening agent. (2) The recording material according to claim 1, wherein an ink retaining layer and an ink transport layer are laminated on a base material. (3) The recording material according to claim 1, wherein the ink transport layer is porous. (4) The recording material according to claim 1, wherein the ink transport layer contains particles that are non-stainable to the recording agent and a binder. (5) The recording material according to claim 1, wherein the ink retaining layer is non-porous.