JPS6141587A - Recording material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a recording material suitably used in an inkjet recording method, and in particular has excellent ink receptivity and clarity of recorded images, and When it is a translucent recording material, it relates to a recording material that has excellent ink receptivity and translucency.

(Prior Art) The inkjet recording method uses various ink (recording liquid) ejection methods, such as an electrostatic suction method, a method that applies mechanical vibration or displacement to the recording liquid using a piezoelectric element, and a method that applies mechanical vibration or displacement to the recording liquid using a piezoelectric element. In this method, small droplets of ink are generated and made to fly by foaming and using the pressure of the foam, and some or all of these droplets adhere to a recording material such as paper to perform recording, but this method generates noise. It is attracting attention as a recording method that allows for high-speed printing and multicolor printing.

Inks for inkjet recording are mainly water-based in terms of safety and recording properties.
Polyhydric alcohols and the like are often added to prevent nozzle clogging and improve ejection characteristics.

The recording material used in this inkjet recording method has conventionally been a recording material made of a base material called ordinary paper or inkjet recording paper provided with a porous ink absorbing layer. However, as the performance of inkjet recording apparatuses improves and becomes more widespread, such as faster recording speeds and multicolor recording, more advanced and wide-ranging properties are being required of recording materials. In other words, the recording medium for inkjet recording in order to obtain high-resolution, high-quality recorded images requires (1) the ink to be fixed on the recording material as quickly as possible, and (2) the ink dots to be Even if the dots overlap, the ink deposited later will not flow into the dots deposited earlier. (3) Although the ink droplets will spread to some extent on the recording material,
(4) The shape of the ink dot should be close to a perfect circle and its circumference should be smooth; (5) The diameter of the ink dot should not be larger than necessary; It is necessary to satisfy basic requirements such as high optical density (optical density) and no blurring around the dots.

Furthermore, in order to obtain high-resolution recorded image quality comparable to color photography using multicolor inkjet recording, in addition to the above-mentioned required performance, (6) the coloring components of the ink must have excellent color development; 7) The ink fixation properties are particularly excellent, as the same number of droplets as the number of ink colors may adhere to the same spot, (8) The surface must be glossy, (9) Whiteness A high level of performance, etc., is required.

In addition, images recorded by inkjet recording have traditionally been used exclusively for surface image observation, but as the performance of inkjet recording devices has improved and become more widespread, recording materials suitable for purposes other than surface image observation have become available. It is becoming demanded. Applications of recording materials other than surface image observation include those used to project recorded images onto a screen, etc. using a slide or an optical device such as an 0HP (overhead/top projector), and to observe those images. , a color separation plate for creating a positive plate for color printing, and a CMF (color mosaic filter) used for color displays such as liquid crystals.

When a recording material is used for surface image observation, the diffused light of the recorded image is mainly observed, whereas for recording materials used in these applications, the problem is mainly the transmitted light of the recorded image. Become. Therefore, it is required to have excellent light transmittance, especially linear light transmittance, in addition to the above-mentioned performance requirements of the general recording material for inkjet recording.

(The problem that the invention is trying to solve) However,
The reality is that there is still no known recording material that satisfies all of these required performances.

Furthermore, most conventional recording materials for surface image observation use a method in which a porous ink absorbing layer is provided on the surface, and a recording liquid is absorbed into the porous voids to fix the recording agent.

On the other hand, when the surface of the ink absorption layer is non-porous, non-volatile components such as polyhydric alcohols in the ink remain on the surface of the recording material for a long time after recording, and the drying and fixing time of the ink is long. However, there were disadvantages in that clothing could get dirty or the recorded image could be damaged if it came into contact with the recorded image.

An object of the present invention is to provide a recording material for inkjet recording that is particularly excellent in ink receptivity and the clarity of recorded images.

Still another object of the present invention is to use an optical device such as a slide or an OHP to project a recorded image onto a screen for observation, a color separation plate when creating a positive plate for color printing, or a liquid crystal display. An object of the present invention is to provide a translucent recording material for inkjet recording that can be used for observation of transmitted light such as CMF used in color displays.

The above and other objects of the invention are achieved by the following invention.

(Disclosure of the Invention) That is, the present invention provides a recording material having an ink retaining layer and an ink permeable layer, in which the ink permeation speed of the ink retaining layer forming material is higher than the ink permeation speed of the ink permeable layer forming material. This is a recording material characterized by the following.

To explain the present invention in detail, the recording material of the present invention has an ink permeable layer on the ink retaining layer made of a material having an ink permeation rate lower than the ink permeation rate of the ink retaining layer forming material. The main feature of the present invention is to provide the following, and the object of the present invention has been mainly achieved thereby.

The recording material of the present invention generally comprises a base material as a support, an ink retaining layer provided on the surface thereof, and an ink permeable layer provided on the ink retaining layer.For example, as a particularly preferred main embodiment, (1) All of the base material, the ink retaining layer, and the ink transmitting layer are translucent, and the recording material as a whole is translucent; (2) At least one of the base material, the ink retaining layer, and the ink transmitting layer is translucent; Examples include an embodiment in which the layer is opaque and the recording material as a whole is opaque.

In any of the above cases, the ink retaining layer may also have the function of a support.

The invention will be explained in more detail using the above two preferred embodiments as representative examples. 1. As the base material that can be used as a support in the present invention, any conventionally known base material such as transparent or opaque can be used. Examples of suitable transparent substrates include films or plates of polyester resins, diacetate resins, triacetate resins, acrylic resins, polypodite resins, cellophane, celluloid, and glass plates. etc. can be mentioned. Preferred opaque substrates include, for example, general paper, cloth,
In addition to wood, metal plates, synthetic paper, etc., the above-mentioned transparent substrates may be treated to make them opaque by known means. Preferably, such a substrate has a thickness in the range of about lθ to 200 ILm.

In the present invention, the ink retaining layer provided on the base material is
It is mainly a hydrophilic material that can accept water-based ink, and is formed from a material having an ink penetration rate higher than the ink penetration rate of the ink permeable layer forming material described below. Preferred materials include albumin, gelatin, casein, starch, cationic starch,
Natural resins such as gum arabic and sodium alginate, polyamide, polyacrylamide, polyvinylpyrrolidone, quaternized polyvinylpyrrolidone, polyethyleneimine, polyvinyl bilicillium halide, melamine resin, polyurethane, carboxymethyl cellulose, polyvinyl alcohol, cation-modified polyvinyl alcohol, polyester , synthetic resins such as sodium polyacrylate, and one or more of these materials may be used as desired. Furthermore,
If necessary, SBR latex,
Resins such as NBR latex, polyvinyl formal, polymethyl methacrylate, polyvinyl butyral, polyacrylonitrile, polyvinyl chloride, polyvinyl acetate, phenolic resin, and alkyd resin may be used in combination.
As a method for forming such an ink retaining layer, a coating solution is prepared by dissolving or dispersing the above-mentioned polymers alone or in a mixture in an appropriate solvent, and the coating solution is coated by, for example, a roll coating method, It is preferable to apply the coating onto the substrate by a known method such as the rod bar coach ink method, air knife coating method, or spray coating method, and then dry it quickly as described above. A single ink-retaining layer is formed by a known method such as a method or a T-die method, and the ink-retaining layer is used so as to have the function of a support.
The ink retaining layer may be formed on the substrate by laminating the sheet onto the substrate, hot-melt coating the polymer material, or the like.

The thickness of the ink retaining layer formed in this way may be within a range capable of retaining ink, and although it depends on the amount of ink to be recorded, it is not particularly limited as long as it is 0.1 gm or more. . Practically speaking, a range of 0.5 to 30 ILm is suitable.

The ink permeable layer used in the present invention and which mainly characterizes the present invention is a thin layer made of natural or synthetic resin provided on the ink retaining layer formed as described above, and the ink permeable layer is a thin layer made of natural or synthetic resin provided on the ink retaining layer formed as described above. When a droplet is deposited, the contact area is rapidly expanded (e.g., within a few seconds) to the extent that the droplet does not overlap excessively with other adjacent droplets, and the droplet penetrates into the ink-retaining layer. It also has the function of promoting ink reception by the ink retaining layer.

The inventor of the present invention conducted extensive research in order to provide the ink retaining layer with the functions described above, and unexpectedly found that the ink permeation rate of the polymer constituting the ink retaining layer into the ink retaining layer L It has been discovered that by forming a thin layer of polymer with a low ink penetration rate, the above functions can be easily achieved. This kind of functionality is
What was truly surprising was that this was achieved even with thin films of polymers which, for example, have no or little solubility in water.

The "ink permeation speed" as used in the present invention is a value expressed by the time it takes for ink to reach the back surface when a layer made of the polymer as described above is formed and ink droplets are attached to the surface thereof.

In reality, the dry film thickness is Ig on a plate of good conductor such as metal.
Forming a layer from the polymer as described above so that m
Place a metal plate electrode with a hole of 2 mm diameter in the center on the surface, place 0.1 cc of ink on the hole in the center,
It can be determined by measuring the time until a current begins to flow between the electrode and the metal base using the conductivity measure. The ink used for measurement was 70% water, 20% diethylene glycol, and polyethylene glycol 9200.
A material containing 10% by weight was used.

The ink permeable layer having the above function is made of a polymer having relatively poor hydrophilicity with respect to the polymer material forming the ink retaining layer, and has a thickness of about 1101 L or less, preferably about 0.1 to 5 pm. This was achieved by forming a thin layer. Polymeric materials useful in forming such thin layers include vinyl acetate, acrylates, ethylene,
Homopolymers or copolymers made of vinyl chloride and other vinyl monomers, and polymers made of the above-mentioned vinyl monomers and various wood-philic vinyl monomers,
Furthermore, polymers such as vinylon, polyurethane, cellulose derivatives, polyester, and polyamide, and the above-mentioned wood-philic polymers for forming an ink-retaining layer, singly or in combination, have a hydrophilic property inferior to that of the ink-retaining layer. It is preferable to select it as such.

Further, the selected polymer may be a solution in an organic solvent, but it is preferably used in the form of an emulsion in an aqueous medium, an organic solvent, or a fine dispersion in an aqueous medium.

When used as an organic solvent solution, it is preferable to use a relatively dilute solution or a concentration such that the formed layer falls within the above range.

One method for forming the ink permeable layer using the above-mentioned materials can be the same method as for forming the ink retaining layer.

The recording material of the present invention having the above-mentioned basic configuration has the advantage that although the ink permeation speed of the ink permeable layer forming material is lower than the ink permeation speed of the ink retaining layer forming material, It is surprising that the recording material has significantly improved ink receptivity and ink fixing properties compared to conventional recording materials that do not have such an ink permeable layer. Although the theoretical basis for this is currently unknown, according to the inventor's mere imagination (the present invention is not limited by such mere imagination), the above-mentioned ink permeable layer is not necessarily continuous. There are countless microscopic gaps in the ink-permeable layer that allow water-based ink to penetrate into the ink-retaining layer, rather than a film, and the surface is irregular on a microscopic scale, resulting in small ink droplets adhering to the layer. quickly diffuses on the surface, expanding their contact area,
Therefore, it is considered that the ink absorption and fixing properties of the ink retaining layer are significantly promoted. Furthermore, since the ink permeable layer of the recording material of the present invention can be formed from a polymer having a lower ink permeation rate than the ink retaining layer, even in a high temperature and high humidity atmosphere, the ink once received can be will not leach onto the surface and contaminate equipment, operators, or the surrounding area, and the surface will not become sticky under high temperature and high humidity conditions.

The above is the basic configuration of the present invention. However, in an embodiment in which the recording material of the present invention is translucent, a translucent material is used as the base material, and when forming the ink retaining layer and the ink transmitting layer, , it is necessary to ensure that these layers do not impair translucency. However, filling with silica, clay, talc, diatomite, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, synthetic zeolite, alumina, zinc oxide, lithopone, satin white, etc., to the extent that the translucency is not impaired. Agents can also be dispersed in the ink retaining layer and/or the ink permeable layer.

In the present invention, sufficient light transmittance means that the recording material exhibits a linear light transmittance of at least 2%, and preferably a linear light transmittance of 10% or more.

If the linear light transmittance is 2% or more, it is possible to project and observe the recorded image onto a screen using OHP, for example, and in order to clearly observe the details of the recorded image,
It is desirable that the linear transmittance is 105 or more.

The linear transmittance T (%) here refers to the amount of light incident perpendicularly to the sample, transmitted through the sample, and at least 8
The spectral transmittance of the straight light that passes through the light-receiving side slit on the extension line of the incident optical path that is separated by more than 0 ■ and is received by the detector is measured using, for example, the 323-type Hitachi self-recording spectrophotometer (manufactured by Hitachi, Ltd.). Then, from the measured spectral transmittance, the Y value of the tristimulus value of the color is determined, and the value is determined by the following formula.

T=Y/Y, X100 (1) T; Linear transmittance Y; Y value Y of the sample. Y value of blank Therefore, the linear light transmittance referred to in the present invention is for straight light, and the diffuse light transmittance (an integrating sphere is provided behind the sample to determine the light transmittance including diffused light. ), opacity (
The white and black backings are placed on the back of the sample and the ratio is calculated. ), which evaluates translucency using diffused light. .

The problem with devices that use optical technology is the behavior of straight-line light, so when evaluating the light transmittance of the recording material to be used in those devices, it is important to check the straight-line transmittance of the recording material. It is particularly important to seek

For example, when observing a projected image on an OHP, in order to obtain a clear and easy-to-see image with high contrast between recorded and non-recorded areas, it is necessary that the non-recorded areas of the projected image be bright, that is, the straight line transparency of the recording material. It is required that the light rate be at a certain level or higher. In an OHP test chart test, in order to obtain an image suitable for the above purpose, the linear transmittance of the recording material should be 2% or more, and in order to obtain a clearer image, preferably 10% or more. More preferably, it is 50% or more. Therefore, a recording material suitable for this purpose must have an in-line transmittance of 2% or more.

Further, in an embodiment in which the recording material of the present invention is opaque, an opaque material may be used for at least one layer among the base material, the ink retaining layer, and the ink permeable layer.

The method of forming each layer used in this embodiment is the same as in the transparency embodiment described above.

In this opaque embodiment, when forming the ink retaining layer and the ink permeable layer, it is possible to use a large amount of the filler to the extent that film forming properties are not impaired, thereby further improving excellent ink receptivity and fixing properties. can.

The present invention has been explained above by illustrating typical aspects of the recording material of the present invention, but of course the recording material of the present invention is not limited to these aspects. Also, the ink retaining layer contains a dispersant, fluorescent dye, p
Various known additives such as H regulators, antifoaming agents, lubricants, preservatives, and surfactants can be included.

Note that the recording material of the present invention does not necessarily have to be colorless, and may be a colored recording material.

As explained above and as demonstrated in the examples below, the recording material of the present invention as described above has significantly improved ink reception and fixation, and for example, it can be used not only in monocolor but also in full color. - When recording, even if recording liquids of different colors adhere to the same spot repeatedly within a short period of time, the recording liquid does not run out or seep, and images with high resolution, clarity, and excellent color development can be obtained. It will be done. Furthermore, when using an optical device such as a slide or OHP to project a recorded image onto a screen, etc. for observation, attached ink droplets are more likely to interfere with other adjacent areas than with conventional recording materials. Since the images are enlarged and fixed to such an extent that they do not overlap excessively, the transmitted light becomes even more uniform, providing a projected image with excellent uniform density. Furthermore, it can be suitably applied to uses other than conventional surface image observation, such as a color separation plate when creating a positive plate for color printing, or a CMF used in a color display such as a liquid crystal.

Hereinafter, the method of the present invention will be explained in more detail according to Examples. Note that parts in the text are based on weight.

Example 1 A polyethylene terephthalate film (manufactured by Toshi) with a thickness of 100 IL was used as a translucent base material, and coating liquid A having the following composition was applied onto this film so that the film thickness after drying was 201 L.
The ink retaining layer was coated by a bar coater method and dried at 60° C. for 20 minutes. Next, the following coating solution B was applied onto the ink retaining layer until the dry film thickness was 3.
Bm and dried at 60° C. for 15 minutes to form an ink-transmissive layer, thereby obtaining a translucent recording material of the present invention.

Coating liquid A composition: -90 to polyvinylpyrrolidone (manufactured by GAF, ink penetration speed in seconds) 15 parts water
85 parts Coating liquid B composition: Carboxymethylcellulose (Shichirogen BS, Dai-Kogyo Seiyaku Co., Ltd., ink penetration speed in seconds) 2 parts water
98 parts The thus obtained recording material of the present invention was colorless and transparent.

Example 2 A recording material of the present invention was obtained in the same manner as in Example 1 except that art paper was used as the base material.

Example 3 A polyethylene terephthalate film (manufactured by Kijin Co., Ltd.) with a thickness of 1001 L was used, and coating liquid A having the following composition was coated on this film using a bar coater method so that the film thickness after drying was 100 JLII. It was dried at 80°C for 1 hour to form an ink retaining layer.Next, the following coating solution B was applied onto the ink retaining layer so that the dry film thickness was 5#Lm, and the coating solution was dried at 80°C for 1 hour. to form an ink permeable layer, and then peel off the ink retaining layer and the ink permeable layer together from the polyethylene terephthalate film.
A transparent recording material of the present invention was obtained.

Coating liquid A composition: Polyvinyl alcohol (PVA 420 manufactured by Kuraray, ink penetration speed seconds 10 parts water
90 parts Coating liquid i Composition; Acrylic acid ester (Guikaratsuku 51235, ink penetration speed in seconds) 5 parts Ethanol 95 parts Example 4 Art paper was used as a base material, and coating liquid A with the following composition was applied on this base material. was coated by a bar coater method so that the film thickness after drying was 25 JLI1, and dried at 50° C. for 20 minutes to form an ink retaining layer. Next, the following coating liquid B was applied onto the ink retaining layer so that the dry film thickness was 2 JLm, and dried at 70° C. for 10 minutes to form an ink permeable layer. I got the material.

Coating liquid A composition: Water-soluble acrylic resin (Corgam HW-7, manufactured by Showa Kobunshi, ink penetration speed in seconds) 20 parts finely divided silica (Syroid #244 manufactured by Fuji Davison) 5 parts water
75 parts Coating liquid B composition: Polyvinyl acetate (Movinyl 303, manufactured by Hoechst, ink penetration speed in seconds) 10 parts water
9 Part O Comparative Examples 1 to 4 Comparative recording materials were prepared in the same manner as Examples 1 to 4, except that the materials for forming the ink retaining layer and the ink permeable layer were reversed.

An on-demand inkjet recording head (on-demand type inkjet recording head that ejects ink using a piezoelectric vibrator) uses the following four types of ink on the recording materials of the above examples and comparative examples.
Discharge orifice diameter 65 layers, piezo vibrator drive voltage 70
Inkjet recording was performed using a recording device having a frequency of 3 KHz.

Yellow ink (composition) c, r, direct yellow 86 2 parts N-methyl-
2-pyrrolidone 10 parts diethylene glycol
20 parts Polyethylene glycol #200 15 parts Water 55 parts Magenta ink (composition) C, 1, Acid Red 35 2 parts N-methyl-2-pyrrolidone 10 parts diethylene glycol
20 parts polyethylene glycol #200 15 parts water 55
Part cyan ink (composition) C, 1, Direct Blue 86 2 parts N-methyl-
2-pyrrolidone 10 parts diethylene glycol
20 parts polyethylene glycol #200 15 parts water 55
Part Black Ink (Composition) C, 1, Food Black 2 2 parts N-methyl-2-pyrrolidone 10 parts diethylene glycol
20 parts polyethylene glycol #200 151
water 55
The evaluation results of the recording materials of the above examples and comparative examples were evaluated in the first part.
Shown in the table. Each evaluation item in Table 1 was measured according to the following method.

(1) Ink fixation time was measured by leaving the recording material at room temperature after recording and measuring the time taken for the ink to dry and stop adhering to the finger when touching the recorded image with the finger.

(2) The dot density was measured for black dots using Sakura Microdensidometer PDM-5 (manufactured by Konishiroku Photo Industries) by applying JIS K 7505 to printed microdots.

(3) OHP suitability was measured as a representative example of optical equipment, and the recorded image was projected onto a screen using OHP.
Judging by visual observation, the non-recorded area is bright, the OD (optical density) of the recorded image is high, and a clear and easy-to-see projection image with high contrast is obtained. O1 The non-recorded area is slightly dark and the recorded image If the OD of is rather low, the pitch width is 0.5■■, and the line with a thickness of 0.251■ cannot be clearly distinguished, Δ, the non-recorded area is quite dark, the OD of the recorded image is quite low, and the pitch width is 1■ ■, thickness 0.3
A case where the line of ■■ could not be clearly distinguished or a case where the non-recorded area and the recorded image could not be distinguished were marked as ×.

(4) Straight line transmittance is determined by measuring the spectral transmittance using a 323-type Hitachi self-recording spectrophotometer (newly manufactured by Hitachi), keeping the distance from the sample to the light-receiving side at approximately 90 square meters, and measuring the spectral transmittance as described above. (
1) It was calculated using the formula.

-41- 20℃ 65 tone 1.5 minutes 1.5 minutes
45 seconds 1.5 minutes 20℃ 8 to 11 minutes
1 min 30 sec 45 sec straight shot rate 76%
78% -1-1''21L degrees
0.9 1.2 1.0 1
．． Oq2m sacrifice 0 0
-20℃ 65 tone 3 minutes 3 minutes
30 minutes or more 10 minutes direct JIJL rate 78%
80% 21L degrees 0.9 1.2 1.1
T.

Claims (1)

[Claims] A recording material having an ink retaining layer and an ink permeable layer, wherein the ink permeation speed of the ink retaining layer forming material is higher than the ink permeation speed of the ink permeable layer forming material.