JPS6112388A - Recording material - Google Patents

Abstract

PURPOSE:To obtain an ink jet recording material having excellent ink receptivity, clearness of recorded images or the like, and having excellent ink receptivity and light-transmitting property where it is a light-transmitting recording material, by providing an ink-permeable layer having specified properties on an ink- holding layer provided on the surface of a base. CONSTITUTION:By using a polymer less hydrophilic than a polymeric material constituting the ink-holding layer, a thin film having a thickness of not larger than about 10mum, preferably, about 0.1-5mum, is provided as the ink-permeable layer. With this construction, ink droplets adhered to the surface of the ink- permeable layer are speedily dispersed on the surface, and the contact area thereof is enlarged, so that the ink receptivity and fixability of the ink are markedly enhanced as compared with the case of a recording material not comprising the ink-permeable layer. In an embodiment in which the recording material is a light-transmitting one, a light-transmitting material is used as a base, and the ink-holding layer and the ink-permeable layer must not impair light- transmitting property, and the recording material is desired to have a linear light transmittance of at least 2%, preferably, not lower than 10%.

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 that is made by providing a porous ink absorbing layer on a base material called ordinary paper or inkjet recording paper. . 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. That is, it can be used as a recording material for inkjet recording to obtain high-resolution, high-quality recorded images.

(1) The ink should be fixed on the recording material as quickly as possible. (2) Even if ink dots overlap, the ink that has adhered later will not flow into the dot that has adhered earlier.

(3) Although the ink droplets diffuse 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 OD of the ink dot ( It is necessary to satisfy basic requirements such as high 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 or the like using an optical device such as a slide or OHP (overhead projector) and observe those images; Examples include color separation plates used to create positive plates for color printing, and CMF (color mosaic filters) used in 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 are disadvantages in that clothing may get dirty or the recorded image may be damaged if it comes 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 is a recording material characterized by having an ink retaining layer and an ink permeable layer. To explain the present invention in detail, the main feature of the recording material of the present invention is that an ink permeable layer with specific properties is provided on the ink retaining layer, and the object of the present invention is mainly achieved thereby. Ta.

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 aspect, ( 1) An embodiment in which the base material, the ink retaining layer, and the ink transmitting layer are all translucent, and the recording material as a whole is translucent; (2) At least one layer of the base material, the ink retaining layer, and the ink transmitting layer. Examples include an embodiment in which the recording material 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.

To explain the invention in more detail using the above two preferred embodiments as representative examples, 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 polyester resins, diacetate resins, triacetate resins, acrylic resins, polycarbonate resins, polyvinyl chloride resins, polyimide resins, cellophane, and celluloid. Examples include films or plates, and glass plates. Preferred opaque substrates include, for example, general paper, cloth, wood,
In addition to metal plates, synthetic papers, etc., the above-mentioned transparent substrates may be treated to make them opaque by known means. Preferably, such a substrate has a thickness of about 10 to 200 JLm.

In the present invention, the ink retaining layer provided on the base material is
It is mainly formed from a hydrophilic material that can accept water-based ink, and preferred examples of such materials include albumin, gelatin, casein, starch,
Cationic starch, gum arabic, natural resins such as sodium alginate, polyamide, polyacrylamide, polyvinylpyrrolidone, quaternized polyvinylpyrrolidone, polyethyleneimine, polyvinylpyricillium halide, melamine resin, polyurethane, carboxymethylcellulose, polyvinyl alcohol, cationically modified polyvinyl Examples include synthetic resins such as alcohol, polyester, and sodium polyacrylate, and one or more of these materials may be used as desired.

Furthermore, in order to reinforce the strength of the ink retaining layer and/or improve the adhesion with the base material, SUR latex, NBR latex, polyvinyl formal, polymethyl methacrylate, polyvinyl butyral, polyacrylonitrile, polyvinyl chloride may be added as necessary. , polyvinyl acetate, phenol resin, alkyd resin, etc. 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 a rod bar coating method, an air knife coating method, or a spray coating method, and then dry it immediately. Either a single ink retaining layer is formed by a known method such as a die method and used so that the ink retaining layer also has the function of a support, or
By a method of laminating the sheet on the base material, a method of hot melt coating the polymer material, etc.
An ink retaining layer may be formed on the base material.

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 pm. In practical terms.

0.5-30 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 intensive research to impart the above-mentioned functions to the ink-retaining layer, and found that, quite unexpectedly, a polymer having a hydrophilicity lower than that of the polymer constituting the ink-retaining layer was deposited onto the ink-retaining layer. It has been discovered that the above functions can be easily achieved by forming a thin layer of polymer.

It was truly surprising that such a function could be achieved even with thin films of polymers that, for example, have no or little solubility in water.

The ink permeable layer having the above functions is made of a polymer having relatively poor hydrophilicity with respect to the polymer material forming the ink retaining layer, so that the ink permeability layer has a hydrophilicity of about 10 pm or less, preferably about 0.
．． This was achieved by forming a thin film with a thickness of 1 to 5 Ji, m. Polymeric materials useful in forming such thin films include homopolymers or copolymers of vinyl acetate, acrylic esters, ethylene, vinyl chloride, and other vinyl monomers, as well as vinyl monomers such as those listed above and various wood-philic vinyl monomers. Polymers consisting of, furthermore, vinylon, polyurethane, cellulose derivatives,
It is preferable to select one of polymers such as polyester, polyamide, and the above-mentioned hydrophilic polymers for forming an ink-retaining layer, either singly or in a mixture, so that the ink-retaining layer has lower hydrophilicity than that of the ink-retaining layer.

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.

The method for forming the ink permeable layer using the above materials may be the same as that for forming the ink retaining layer.

Although the recording material of the present invention having the above-mentioned basic structure has a hydrophilicity of the ink permeable layer which is inferior to that of the ink retaining layer, the recording material of the present invention has such a structure. It is surprising that the ink receptivity and ink fixing properties are significantly improved compared to conventional recording materials that do not have 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. It is thought that the ink absorbency and fixing properties of the ink retaining layer are significantly promoted by rapidly diffusing on the surface and expanding their contact area. In addition, since the ink permeable layer of the recording material of the present invention is formed from a polymer (which has lower hydrophilicity than the ink retaining layer), even in a high temperature and high humidity atmosphere, once the ink is received. The ink may leach onto the surface and cause damage to the equipment,
Operators L and N do not contaminate the surrounding area,
Also, the surface will not become sticky under high temperature and high humidity conditions.

The above is the basic structure of the present invention. 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, to the extent that the translucency is not impaired, for example, silica, clay, talc, diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, synthetic zeolite, alumina, zinc oxide, 1 nodopon, satin white, etc. Fillers can also be dispersed in the ink-retaining 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 light transmittance is 10% or more.

The linear light transmittance T (%) here means that the light enters the sample perpendicularly, passes through the sample, and passes through the receiving side slit on the extension of the incident light path that is at least 8 C■ away from the sample deer 1. The spectral transmittance of the straight light received by the detector is measured using, for example, a 323-type Hitachi self-recording spectrophotometer (Hitachi, Ltd.), and the tristimulus values of the color are determined from the measured spectral transmittance. The Y value is calculated using the following formula.

T=Y/Y, X100 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 to make sure that the non-recorded areas in the projected image are bright, that is, the straight line of the non-recorded material. It is required that the light transmittance be at a certain level or higher. 0) (In a test using a test chart at % or more, and more preferably 50% or more.Therefore, a recording material suitable for this purpose must have a linear transmittance of 2% or more. be.

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 described above by exemplifying 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. In addition, in any embodiment, 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 has significantly improved ink reception and fixing, for example, in the case of monochrome, of course. During full-color recording, even if recording liquids of different colors repeatedly adhere to the same spot 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 0I (P) to project a recorded image onto a screen, etc. for observation, attached ink droplets are more likely to be attached to other adjacent recording materials than with conventional recording materials. Since it is magnified and fixed to about 1 degree without overlapping the area, the transmitted light becomes even more uniform, giving a projected image with excellent uniform density.6 Furthermore, a color printing positive plate is It can be suitably applied to uses other than conventional surface image observation, such as color separation plates during production or CMF used in color displays such as liquid crystals.

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 1OOpL11 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 20
pm' by the bar coater method, and
It was dried at ℃ 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 31 Lm, and dried at 60° C. for 15 minutes to form an ink permeable layer. I got the material.

Coating liquid A composition: polyvinylpyrrolidone, -90 (manufactured by GAF), 15 parts water

85 parts Coating liquid B composition: Carboxymethyl cellulose (Shichirogen BS, manufactured by Dai-Kogyo Seiyaku) 2 parts water
98 parts The thus obtained recording material of the present invention was colorless and transparent. An on-demand inkjet recording head (discharge orifice diameter 65 JLm, piezo oscillator drive voltage 70 V,
Inkjet recording was performed using a recording device having a frequency of 3 KHz).

Yellow ink (composition) C,! , Direct Yellow 86 2 parts N-methyl-
2-pyrrolidone 10 parts diethylene glycol
20 parts polyethylene glycol #200 15 parts water 55
Part magenta ink (set 1#) C,1, Acid Red 35 2 parts N-methyl-2-pyrrolidone 10 parts diethylene glycol
20 parts polyethylene glycol #200 15
Department water
55 parts 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 parts Black ink (composition) C, 1, Food Black 2 2 parts N-methyl-2-pyrrolidone 10 parts Diethylene glycol
20 parts polyethylene glycol 9200 15 parts water 5
5 copies The evaluation results of the recording material of this example are shown in Table 1.

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 calculated using Sakura Microdensidometer PD by applying JISK7505 to the printed microdots.
The black dots were measured using M-5 (manufactured by Konishiroku Photo Industry).

(3) OHP suitability was measured as a representative example of optical equipment, and the recorded image was projected onto a screen using OHP.
Judgment is made by visual observation. 0 indicates that the non-recorded area is bright, the recorded image has a high 00 (optical density), and a clear and easy-to-see projected image with high contrast is obtained, and 0 indicates that the non-recorded area is slightly dark and the recorded image is high. The OD of the image is slightly low.

Pitch width 0.5 mm, thickness 0.25 mm (7) If the line cannot be clearly distinguished, Δ, the non-recorded area is quite dark, the OD of the recorded image is quite low, pitch width 1 mm, thickness 0
．． A case where the 3 mm line could not be clearly distinguished or a case where the non-recorded area and the recorded image could not be distinguished was designated as X.

(4) Straight line transmittance was determined by measuring the spectral transmittance using a 323-type Hitachi self-recording spectrophotometer (Hitachi, Ltd.), keeping the distance from the sample to the light-receiving side at approximately 9 cm.
1) It was calculated using the formula.

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. This recording material was white and opaque. Inkjet recording similar to that in Example 1 was performed on this recording material, and the recording characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3 A polyethylene terephthalate film (manufactured by Kijin Co., Ltd.) with a thickness of 100 m was used, and coating liquid A having the following composition was applied onto this film by a percoater method so that the film thickness after drying was 11007 t. Then, it was dried at 80° C. for 1 hour to form an ink retaining layer. Next, apply the following coating liquid B
was coated on the ink retaining layer so that the final dry film thickness was 5 m, and dried at 80°C for 20 minutes to form an ink permeable layer. The transparent layer was also peeled off to obtain a transparent recording material of the present invention.

Coating liquid A composition: Polyvinyl alcohol (PVA 420 manufactured by Kuraray) 10 parts water
90
Part Coating liquid B composition: Acrylic acid ester (Daikalak 51235) 5 parts Ethanol 95 parts This recording material was subjected to inkjet recording in the same manner as in Example 1, and the recording characteristics were evaluated in the same manner as in Example 1. did. The result is the first
Shown in the table.

Example 4 Art paper was used as a base material. Coating solution A having the following composition was applied onto this base material by a percoater method so that the film thickness after drying was 25 JLw, and the coating solution was heated at 50 °C for 20 The ink retaining layer was formed by drying for 1 minute. Next, Coating Solution B described below was applied onto the ink retaining layer so as to have a dry film thickness of 2 pm, and dried at 70°C for 10 minutes to form an ink permeable layer.

A non-transparent recording material of the present invention was obtained.

Coating liquid A composition; water-soluble acrylic resin (Korgum HW-7, Showa Kobunshi) 20 parts fine powder silica (Syroid #244 Fuji Davison) 5 parts water
75 parts Coating liquid B composition: Polyvinyl acetate (Movinyl 303, manufactured by Hoechst) 10 parts water
90 copies of this recording material were subjected to inkjet recording in the same manner as in Example 1, and the recording characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 1.2.4 Example 1. except that no ink permeable layer was formed.
A comparative recording material was prepared in the same manner as in 2.4, and inkjet recording was performed on it in the same manner as in Example 1. Table 1 shows the results of the evaluation of recording characteristics conducted in the same manner as in Example 1.

Comparative Example 3 A comparative recording material was prepared in the same manner as in Example 3, except that no ink retaining layer was formed, and inkjet recording was performed on this material in the same manner as in Example 1. Table 1 shows the results of the evaluation of recording characteristics conducted in the same manner as in Example 1.

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6% 78% -5.1 1.0 L 0.9 1.2 1.0 1.0 Store RH 3 minutes 3 minutes Sticky for 30 minutes or more 10 minutes

Claims (1)

[Claims] A recording material comprising an ink retaining layer and an ink permeable layer.