JPS6135276A - Recording material - Google Patents

Abstract

PURPOSE:To provide a light-transmitting recording material for ink jet recording which is excellent in ink receptivity and clearness of recorded images, by providing an ink-holding layer and an ink-permeable layer consisting of fine particles. CONSTITUTION:The ink-holding layer is formed mainly of a hydrophilic material capable of receiving a water base ink, e.g., polyvinyl pyrrolidone. The ink- permeable layer consisting of fine particles may be provided by, for example, a method wherein a liquid comprising a resin such as polyvinyl acetate is applied to the ink-holding layer in a predetermined thickness, and a medium is removed by paying attention to the drying temperature. To produce the recording material, for example, a polyethylene terephthalate film is used as a light-transmitting base, a coating liquid comprising 15pts.wt. of polyvinyl pyrrolidone and 85pts.wt. of water is applied to the film by a bar coater method, followed by drying to provide the ink-holding layer. Then, a coating liquid comprising 10pts.wt. of polyvinyl acetate and 90pts.wt. of water is applied to the ink-holding layer, and is dried to provide the ink-permeable layer consisting of fine particles, thereby obtaining the light-transmitting recording material.

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 such as ordinary paper or a recording material called inkjet recording paper provided with a porous ink absorbing layer. However, as the performance of inkjet recording apparatuses increases and becomes more widespread, such as faster recording and multi-color recording, more advanced and wide-ranging properties are being required of recording materials. In other words, in order to obtain high-resolution, high-quality recorded images, the recording material for inkjet recording must (1) be able to fix the ink to the recording material as quickly as possible, and (2) have overlapping ink dots. (3) Even if the ink droplets deposited later do 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 oD (optical density) of the ink dot should be ) is high and the area around the dots is not blurred, etc., and other basic requirements must be met.

Furthermore, in order to obtain high-resolution recorded image quality comparable to color photography using multicolor inkjet recording, in addition to the above-mentioned performance requirements, (6) the coloring components of the ink must have excellent coloring properties.

(7) The ink fixation properties are particularly impaired because the same number of droplets as the number of ink colors may adhere to the same spot, (8) The surface is glossy, (9) Performance such as high whiteness 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. Other uses for recorded materials other than 0 surface image observation, which are becoming increasingly required, include recording images projected onto a screen using optical equipment such as slides and 0HP (overhead/overhead projectors), and observing those images. Examples include those used for color printing, color separation plates for creating positive plates for color printing, and CMFs (color mosaic filters) used for color displays such as liquid crystals.

When a recording material is used for surface image observation, mainly the diffused light of the recorded image is observed, whereas for recording materials used in these applications, mainly the transmitted light of the recorded image is observed. becomes a problem. 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 measuring transmitted light a of 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 comprising an ink retaining layer and an ink permeable layer, the ink permeable layer being a fine particle 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 consisting of a fine particle layer is provided on the ink retaining layer, and the object of the present invention is mainly achieved by this. achieved.

The recording material for Suekan IJI generally includes a base material as a support,
It consists of an ink retaining layer provided on the surface and an ink permeable swirl layer which is a fine particle layer provided on the ink retaining layer.For example, as a particularly preferred main aspect, (1) a base material, an ink retaining layer and (2) An embodiment in which all of the ink-transmitting layers are translucent, and the recording material as a whole is translucent; Examples include a mode in which the entire surface is opaque.

In any of the above cases, the ink retaining layer may also serve as 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, celluloid, etc. Examples include films or plates, and glass plates. In addition, preferred examples of opaque J-based substrates include general paper, cloth, wood, metal plates, synthetic papers, etc., as well as the above-mentioned transparent materials, and Ti materials made opaque by known means. I can give you the processed ones. Such a substrate has a thickness of about lθ~200 ILm
Preferably, it is within the range of .

In the present invention, the ink retaining layer provided on the base material is
It is mainly formed from hydrophilic old materials that can accept water-based inks, and preferred 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, SBR latex, NBR latex, polyvinyl formal, polymethyl methacrylate, polyvinyl butyral, polyacrylonitrile, polyvinyl chloride may be added as necessary. , polyvinyl acetate, phenolic resin.

Resins such as alkyd resins 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, '-/F Coated on the base material by a known method such as a bar coat ink method, an air knife coating method, a spray coating method,
It is preferable to quickly dry the material after that, and a single ink-retaining layer is formed from the above materials by a known method such as a heat stretching method or a T-die method, and the ink-retaining layer is used as a support. or use it so that it has the functions of
Alternatively, a method of laminating the sheet on the base material,
The ink retaining layer may be formed on the base material by a method such as hot melt coating with the above polymer material.

The thickness of the ink holding layer formed in this way may be within a range that can hold the 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 gm is suitable.

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

The inventor of the tree conducted extensive research in order to impart the above-mentioned functions to the ink-retaining layer, and unexpectedly found that the ink-retaining layer was coated with a material having a hydrophilicity comparable to or having a hydrophilic level as that of the polymer constituting the ink-retaining layer. The inventors have discovered that the above functions can be easily achieved by forming a thin layer of fine particles of a polymer with inferior properties. It was truly surprising that such a function could also be achieved with a thin layer of fine particles of a polymer which, for example, has no or little solubility in water.

The ink-permeable layer having the above-mentioned functions is made of fine particles of a polymer having hydrophilicity of about 110% or less than that of the polymer material forming the ink-retaining layer.
This was achieved by forming a thin layer with a thickness of less than 1 L, preferably in the range of about 0.1 to 5 pm. Polymeric materials useful in forming such thin layers 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 hydrophilic vinyl monomers. Polymers consisting of, as well as vinylon, polyurethane, and cellulose! Conductors, polymers such as polyesters, polyamides, and the above-mentioned wood-philic polymers for forming the ink-retaining layer are selected singly or as a mixture to have hydrophilicity comparable to or inferior to that of the ink-retaining layer. is suitable.

Also, i2! The selected polymers are preferably used in the form of emulsions in organic solvents or aqueous media, or as fine dispersions in organic solvents or aqueous media. Alternatively, it is preferable to use it as a dispersion so that the layer formed falls within the above range.

The method of forming a permeable layer consisting of fine particles using the above-mentioned materials is to apply the above-mentioned resin liquid to a certain thickness on the ink-retaining layer, and then dry the polymer by paying attention to the drying temperature. It can be easily prepared by removing the medium by dry shelling at a temperature at which the fine particles do not fuse together or do not fuse excessively.

The depth of the ink permeable layer made of fine polymer particles formed in this manner is not particularly limited as long as it is 10 ILm or less, although it depends on the amount of ink required for recording. A range of .1 to 5 m is suitable. It is also possible to form the permeable layer using a material that swells or dissolves the permeable membrane and collapses the fine particle structure after the water-based ink permeates, but generally it is not suitable for high temperatures and high humidity. In order to be able to use it even under the harsh conditions shown below and to protect the ink retaining layer under such conditions, we have developed a permeable layer-forming material that can form a layer that is difficult to swell and dissolve with water-based ink. Preferably.

The fine particles constituting the permeable layer produced as described above may be within the particle size range of a general polymer emulsion or dispersion, for example, particles with a size of about 0°O1 to 0.51Lm. By using such particles, which are preferred, countless gaps are formed between the particles through which the aqueous ink can sufficiently permeate through capillary action, and the remarkable fI effect of the present invention is achieved.

In the recording material of the present invention having the above-mentioned basic structure, although the hydrophilicity of the ink-permeable layer is comparable to or inferior to the hydrophilicity of the ink-retaining layer, the unexploited recording material 1j has the following properties: It is surprising that the ink receptivity and ink fixing properties are significantly improved compared to conventional recording materials that do not have such an ink permeable layer.

This dramatic effect is due to the fact that there are countless tiny gaps in the ink-permeable layer that allow water-based ink to penetrate into the ink-retaining layer, making the ink-permeable layer porous, and the surface of the ink-retaining layer is porous. As a result, the attached ink droplets quickly spread on its surface, expanding their contact area, and the capillary action of countless micropores improves the ink absorption and fixation by the ink-retaining layer. This is one in which sex is significantly promoted.

In addition, the ink permeable layer of the recording material for unreleased IJI is
Since the ink retaining layer can be formed from a polymer with similar or lower hydrophilicity than the ink retaining layer, even in a high temperature and high humidity atmosphere, the ink that has been received will leach onto the surface and cause damage to equipment, operators, or the surroundings. The surface will not become sticky under high temperature and high humidity conditions.

The above is the basic structure of the present invention, but 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.

Fillers such as clay, talc, diatomaceous material ±, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, synthetic zeolite, alumina, summer lead oxide, lithopone, and sachin white are dispersed in the ink retaining layer and/or ink permeable layer. You can also do it.

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 the recorded image onto a screen and observe it using O'HP, for example.
It is desirable that the linear light transmittance is 105 or more in order for the recorded image to be observed at a clear E51 level.

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, which is on the extension of the incident optical path that is further away than the C intestine, and is received by the detector is set to 1.For example, use a 323-type Hitachi self-recording spectrophotometer (newly manufactured by Hitachi), etc. The Y value of the tristimulus value of the color is determined from the measured spectral transmittance using a linear equation.

7=y/y, xtoo (1) T; Linear transmittance Y: Y value of sample Y, Y value of blank rate (install an integrating sphere behind the sample to determine the 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. In an OHP test chart test, in order to obtain an image suitable for the above purpose, the linear transmittance of the recording material is 2% or more, and in order to obtain a clearer image, it is preferably 105 or more. More preferably, it is 50% or more. Therefore, a recording material suitable for this purpose needs to 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 in section 2.

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. 0, which can be done.

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. In this embodiment, the ink retaining layer may contain various known additives such as a dispersant, a fluorescent dye, a pHWffi agent, an antifoaming agent, a lubricant, a preservative, and a surfactant.

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, in the case of monochrome as well as full color. When recording, even if different colors of recording liquid adhere to the same spot repeatedly within a short period of time, there is no phenomenon of recording liquid flowing out or seeping, and images with high resolution, clarity, and excellent color development can be obtained. . 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 JL was used as a translucent material, and coating liquid A having the following composition was applied onto this film so that the film thickness after drying was 20 JL.
, coated by the barco-tar method so that it becomes ILI,
The ink retaining layer was formed by drying at 60°C for 20 minutes.Then, the following coating solution B was applied onto the ink retaining layer so that the dry film thickness was 3 mm, and the coating solution was dried at 60°C for 15 minutes. This was dried for a minute to form an ink permeable layer consisting of fine particles, thereby obtaining a translucent recording material of the present invention.

Coating liquid composition: Polyvinylpyrrolidone (K-90, manufactured by GAF) 15 parts water
85
Part Coating Liquid B Composition: Polyvinyl acetate (Movinyl 303, manufactured by Hoechst) to Part Water
90 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. This recording material was white and opaque, and the size of the micropores was the same as in Example 1.

Example 3 A polyethylene terephthalate film (manufactured by Music University) with a thickness of 100 mm was used, and coating liquid A with the following composition was applied onto this film using a bar coater method so that the film thickness after drying was 100 mm. The ink retention layer was formed by drying at 80°C for 1 hour and 20 minutes.Next, the following coating solution B was applied onto the ink retention layer so that the dry film thickness was 51 parts m. The transparent recording material of the present invention is coated on the base material and dried at 80° C. for 20 minutes to form an ink permeable layer made of fine particles. Obtained. - Coating liquid composition: Polyvinyl alcohol (PVA 420, manufactured by Kuraray) 10 parts water
90
Part Coating liquid B composition: Acrylic acid ester (Sevian A45125, manufactured by Daicel) 10 parts water
90
The following four types of ink were applied to the recording materials obtained in Examples 1 to 3 above using an on-demand inkjet recording head (with an ejection orifice diameter of 65 mm) that ejects ink using a piezo vibrator. Inkjet recording was carried out using a recording device having a piezo vibrator drive voltage of 70 V and a frequency of 3 KHz).

Yellow ink (composition) C0! , Direct Yellow 86 2 parts N-methyl-
2-pyrrolidone 10 parts diethylene glycol
20 parts polyethylene glycol well 200 15f
ill 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 #20Q 151
1J water
55 parts Black ink (composition) C, 1, food black 2 2 parts N-methyl-2-pyrrolidone 10 parts diethylene glycol
20-v & polyethylene glycol #200 1
5fifl water
Table 1 shows the evaluation results of the recording materials of Examples 1 to 3 containing 55 copies. Each evaluation item in Table 1 was measured according to the following method.

(1) 71 hours of ink retention was determined 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.
Judging by visual observation, the non-recorded area is bright, the recorded image has a high 00 (optical density), and the projection image that is easy to see with high contrast bright IJI is 0, the non-recorded area is slightly dark, The OD of the recorded image is slightly low, the pitch width is 0.5 mm, and the thickness is 0.25 mm f)l
Δ indicates that a cannot be clearly distinguished, the non-recorded area is quite dark, the OD of the recorded image is quite low, the pitch is 101 mm,
A case in which a line with a thickness of 0.3 mm could not be clearly distinguished or a case in which a non-recorded area and a 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 (newly manufactured by Hitachi), keeping the distance from the sample to the light-receiving side at approximately 9 cm, and measuring the spectral transmittance as described above (
1) It was calculated using the formula.

Comparative Examples 1 to 3 Examples 1 to 3 except that no ink permeable layer was formed.
Comparative recording materials were prepared in the same manner as in Example 3, and then inkjet recording was performed in the same manner as in Examples 1 to 3. The results of evaluation of recording characteristics conducted in the same manner as in Examples 1 to 3 are shown in Table tJS1.

(1000 public confessions) -Nanie 1-3〈- One example- 1ヱ Danko Z! ]Otsu 1 咋b 20℃E15m 45 seconds 45
Seconds 40 seconds 20℃ Section 85 1 1 minute
1 minute 40 seconds straight weight J1 78%
80% 5, Construction”E 1
．． 1 1.0 1.020℃65
211 3 minutes 3 minutes 20℃ 8
5DH Unrecordable Unrecordable Unrecordable color"
Shitoru” (” ・80% 8
0% Upper-2- Upper 1 Filter 0.8
1.0 1. OQ once-e-aptitude
O.

Claims (1)

[Claims] A recording material comprising an ink retaining layer and an ink permeable layer, the ink permeable layer being a fine particle layer.