JPS6135989A - Material to be recorded - Google Patents

Abstract

PURPOSE:To enhance not only ink receptivity and image sharpness but also blocking resistance, in a material to be recorded for ink jet recording having an ink holding layer and an ink pervious layer, by dispersing a powder throughout the ink pervious layer. CONSTITUTION:An ink holding layer with a thickness of about 0.5-30mum comprising a hydrophilic material, for example, alubmin, gelatine or starch is provided on a substrate with a thickness of about 10-200mum such as paper, cloth or a resin film an ink pervious layer comprising a thin natural or synthetic resin film having a powder dispersed therein. As the resin, a polymer of which the hydrophilicity is equal or inferior to that of the polymer of the ink holding layer, for example, a vinylon or polyurethane is designated and the thickness of the thin film is about 10mum or less. As the powder, a fine powder such as silica or clay with a particle size of 20mum or less is designated and added in an amount of 1-100wt% of the polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of Application The present invention relates to a recording material suitably used in an inkjet recording method, and particularly relates to ink receptivity, clarity of recorded images,
The present invention relates to a recording material that has excellent conveyance properties in a printer, anti-blocking properties, etc., and when the recording material is a translucent recording material, 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, and some or all of them adhere to a recording material such as paper to perform recording. It is attracting attention as a recording method that causes fewer occurrences and 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. That is, it can be used as a recording material for inkjet recording in order 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 spread to some extent on the recording material,
(4) The shape of the ink dot should be close to a perfect circle, and the circumference should be smooth. It is necessary to satisfy basic requirements such as high optical density (optical density) and no blurring around the edges.

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 (10) Smooth conveyance when applied to a printer, etc. are 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. Applications of recorded materials other than 0 surface image observation, which are becoming increasingly required, include projecting recorded images onto a screen, etc. using an optical device such as a slide or 0HP (overhead projector), and observing those images. , 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, 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.

Conventionally, recording materials used for the above-mentioned applications have a translucent base material and an ink-receiving layer provided on the base material. Recording materials with excellent ink absorption properties are known.

Various materials are used to form the ink-receiving layer in such recording materials, but because the ink used is water-based as mentioned above, some materials have excellent ink-receiving layers. Hydrophilic materials such as polyamide and polyvinyl alcohol are attracting attention as materials capable of imparting ink absorption properties.

However, when the ink-receiving layer is formed from the above-mentioned wood-philic material, it has the disadvantage that it absorbs moisture in the air and becomes sticky, and as a result, dust and the like adhere to the surface of the recording material. Furthermore, recording materials may stick to each other when stacked, fingerprints may adhere to them when they are touched with fingers during handling, or the recording materials may stick to each other when they are loaded into a recording device and recorded. Adhesion occurred between the recording material and the feeding roller, making feeding of the recording material unstable or impossible, resulting in inconveniences such as an inability to obtain a good operating state of the recording device.

'The present invention was made in view of these problems,
The purpose is to fully satisfy the above-mentioned required characteristics, in particular, to have excellent ink absorption and translucency, and to have a non-sticky ink receiving surface. It is an object of the present invention to provide a recording material that can be applied to applications in which transmitted light of a recorded image is observed or utilized and is suitable for inkjet recording.

Item L and other objects of the invention are achieved by the invention as follows.

(Disclosure of the Invention) That is, the present invention is a recording material having an ink retaining layer and an ink permeable layer, characterized in that powder is dispersed in the 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 powder is further dispersed in the ink permeable layer. The object of the present invention was 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, an ink permeable layer provided on the ink retaining layer, and powder dispersed in the ink permeable layer. For example, as a particularly preferred main aspect, (1) the base material, the ink holding layer, and the ink transmission layer in which powder is dispersed are all 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 permeable layer in which powder is dispersed 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 such as, and glass plates. Preferred examples of the opaque substrate include general paper, cloth, wood, metal plate 1 synthetic paper, and the above-mentioned transparent substrates treated to make them opaque by known means. Preferably, such substrates have a thickness in the range of about lθ to 200 pm.

In the present invention, the ink retaining layer provided on the base material is
It is mainly formed from a water-repellent 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, polyvinyl bilicylium 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 to the base material, SBR latex, NBR latex, polyvinyl formal, polymethyl methacrylate, polyvinyl butyral, polyacrylocotrilyl, polychloride may be added as necessary. Vinyl, 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, 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
The ink retaining layer may be formed on the substrate by a method such as laminating the sheet onto the substrate, or coating the polymer material with a hot melt coating.

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 pLm is suitable.

The ink permeable layer used in the present invention and which primarily characterizes the present invention is a thin layer made of natural or synthetic resin provided on the ink retaining layer formed as described above. When a droplet of ink is deposited on the surface of a powder on which the powder is dispersed, the contact area is quickly increased (e.g., for several seconds) to the extent that the droplet does not overlap excessively with other adjacent droplets. (2) Expands the ink, promotes penetration into the ink holding layer, and reception of the ink by the ink holding layer, and further prevents surface stickiness, improves transportability of the recording material in the printer, and resistance to prodding when stacking. It has the function of directing people, etc.

The inventor of the present invention conducted extensive research in order to impart the above-mentioned functions to the ink retaining layer, and unexpectedly found that the ink retaining layer had a hydrophilicity of the same level or the same level as the polymer constituting the ink retaining layer. It has been found that the above function can be easily achieved by forming a thin layer made of a polymer having a poor quality and having powder dispersed therein. It was truly surprising that such a function could be achieved even with thin layers of polymers which, for example, have no or little solubility in water.

The ink-permeable layer having the above-mentioned functions is made of a polymer and powder that is equally or relatively less hydrophilic than the polymer material forming the ink-retaining layer, and weighs approximately 1.0 g.
This was achieved by forming a thin layer with a thickness of less than 0.1 pm, 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.

and polymers consisting of vinyl monomers and various hydrophilic vinyl monomers as described above, polymers such as vinylon, polyurethane, cellulose derivatives, polyesters, polyamides, and the above-mentioned wood-philic polymers for forming an ink-retaining layer, singly or in mixtures. It is preferable to select a material having lower hydrophilicity than the ink-retaining layer compared to the ink-retaining layer.

The powder used in the present invention has a particle size of 20 pLm.
The following fine powders are preferred, such as silica, clay, talc, diatomite, calcium carbonate, calcium sulfate,
Examples include inorganic powders such as barium sulfate, aluminum silicate, aluminum, synthetic zeolite, alumina, zinc oxide, lithopone, and satin white. Examples of organic powders include higher fatty acids or their salts, such as aluminum stearate and calcium stearate. Anionic, cationic, nonionic, and amphoteric surfactants that are solid at room temperature, such as sodium dodecylbenzenesulfonate, sodium laurylsulfonate, potassium laurylsulfonate,
Examples include sodium stearyl sulfonate, polyethylene glycol nonylphenyl ether with a relatively high HLB, and plastic pigments such as benzoguanamine resin powder and acrylic resin powder.

The polymer forming the ink-permeable layer 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 or body. If so, it is preferable to use a relatively dilute solution or a concentration such that the layer formed falls within the above range.

In the present invention, by suspending or dispersing the required amount of powder particles in the coating liquid, a structure in which the powder particles are dispersed in the ink permeable layer can be obtained. 1 to 100% by weight, based on the polymer, is preferred. If the amount of powder particles added exceeds 100% by weight, the film forming properties of the polymer will be impaired, and if the amount is less than 1% by weight, the anti-adhesion effect will be low.

The method for forming the ink permeable layer using the above materials is the same method as for forming the ink retaining layer described above, or a polymer solution for the ink permeable layer that does not contain powder is used to form the ink permeable layer. A method may also be used in which a powder is applied to the retaining layer before it is dried, and the applied powder is embedded in one layer of the polymer.

The recording material of the present invention having the above-mentioned basic structure has better ink receptivity, ink fixing property, blocking resistance, and performance in a recording device, compared to a recording material that does not have powder on the ink permeable layer. It is surprising that the transportability is significantly improved.

The amount of powder dispersed in the permeable layer and the powder itself have many capillary voids, and the ink diffuses through the ink permeable layer at a high speed due to the capillary phenomenon.
It becomes a wide area and reaches the ink retaining layer. That is, it is considered that the synergistic effect of the polymer forming the permeable layer and the powder provided therein significantly improves ink receptivity, ink fixability, blocking resistance, transportability, etc.

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 an 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 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 separated by more than cm and is received by the detector is measured using, for example, a Hitachi type 323 self-recording spectrophotometer (Hitachi, Ltd. model). The Y value of the tristimulus value of one color is determined from the measured spectral transmittance, and is determined by the following formula.

T=Y/Y, rate (install an integrating sphere behind the sun sill 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 tests using OHP test charts, in order to obtain images suitable for the purpose listed in L,
The in-line transmittance of the recording material should be 2% or more, preferably 10% or more to obtain a clearer image, and more preferably 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 form, when forming the ink retaining layer and the ink permeable layer, C
A large amount of the filler can be used to further improve ink receptivity and fixing properties.

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 described above and as demonstrated in the Examples below, the recording material of the present invention as described above is capable of receiving ink,
Fixation has been significantly improved, and at the same time, the powder particles dispersed in the ink permeable layer eliminate the stickiness of the surface under high humidity, and the transportability and anti-blocking properties within the printer have been significantly improved. For example, in the case of full-color recording as well as mono-color recording, even when recording liquids of different colors adhere to the same spot repeatedly within a short period of time, there is no phenomenon of recording liquid flowing out or seeping, and high resolution is achieved. Clear images with excellent color development are always 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 and Reference 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#L 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 lo#. L
s by a bar coater method and dried at 60°C for 20 minutes to form an ink retention layer.Next, the following coating solution B was applied on the ink retention layer to a dry film thickness of 1.
The ink was coated to a thickness of 71 m 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; water-soluble acrylic resin (Kogamu 7, manufactured by Showa Kobunshi) 20 parts polyvinyl alcohol (PVA-420, manufactured by Kuraray) 5 parts water
75 parts Coating liquid B composition: Hydrophilic urethane resin (Tricoat G, manufactured by Taiho Industries) 10 parts Finely divided silicic acid (Syroid #161, manufactured by Fuji Davison) 5 parts Acetone
85 parts The thus obtained recording material of the present invention was colorless and transparent.

Example 2 A polyethylene terephthalate film (manufactured by Ondai) with a thickness of 100 μm was used, and coating solution A with the following composition was applied onto this film using a bar coater method so that the film thickness after drying was 100 μm. The following coating solution B was applied and dried under 7 conditions for 1 hour at 80°C to form an ink retaining layer.
was applied onto the ink retaining layer so that the dry film thickness was 3 JLm, and dried at 80°C for 20 minutes to form an ink permeable layer. were peeled together to obtain a translucent recording material of the present invention.

Coating liquid A composition; Polyvinyl alcohol (PVA-220, manufactured by Kuraray) 5 parts Polyvinylpyrrolidone (PVPK-90, manufactured by GAF) 5 parts Water
90
1 part Coating liquid B composition; , carboxymethyl cellulose (Celogen BS, manufactured by Dai-Kogyo Seiyaku) 2 parts fine powder silicic acid (Erosil MOX80, manufactured by Nippon Erogil) 1 part water
97 parts Example 3 The same film as used in Example 1 was used as the base material, and coating solution A with the following composition was applied onto this base material so that the film thickness after drying was 8 wells. It was coated by a bar coater method and dried at 50° C. for 20 minutes to form an ink retaining layer.・Next, apply the following coating liquid B onto the ink retaining layer,
The ink was coated to a dry film thickness of 2 pm and dried at 70° C. for 10 minutes to form an ink permeable layer, thereby obtaining an opaque recording material of the present invention.

Coating liquid A composition: Hydroxyethyl cellulose (HEC AH-15, manufactured by Fuji Chemical) 5 parts water
95 parts Coating liquid B @ composition; Acrylic resin (Guikaratsuku S-1235, manufactured by Daido Kasei) 5 parts Finely divided silicic acid (Zeolex 35F, J, B, manufactured by Two Par) 2 parts Ethanol 93 parts Examples 4 to 5 As powder particles , except that the following powder particles were used:
A translucent recording material of the present invention was obtained in the same manner as in Example 1.

Kazumi' L animal A - 5 parts of talc (SWS, manufactured by Ueya Kaolin) - 5 parts of diatomaceous earth (Super FLoss, manufactured by Ueya Kaolin) Comparative Example 1 No ink permeable layer was formed A comparative recording material was prepared in the same manner as in Example 1 except for the following.

Comparative Example 2 A comparative recording material was produced in the same manner as in Example 1, except that no ink retaining layer was formed.

Comparative Examples 3 to 4 Comparative recording materials were prepared in the same manner as in Examples 1 and 2, except that no powder particles were used in the ink permeable layer.

An on-demand inkjet recording head (with an ejection orifice diameter of 65 cm, Inkjet recording was performed using a recording device having a piezo vibrator drive voltage of 70 V and a frequency of 3 KHz.

Yellow ink (composition) C, 1, 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 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
Part black ink (composition) c, r, food black 2 2 parts N-methyl-2-pyrrolidone 10 parts diethylene glycol
20 parts Polyethylene glycol #200 15 parts Water 55 parts The evaluation results of the recording material 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 OD (optical density) of the recorded image is high, and a clear and easy-to-see projected image with high contrast is obtained, while the non-recorded area is slightly dark and the recorded image is 0. Δ indicates that the OD of the image is rather low, the pitch width is 0.5 layers, and the line of thickness 0.25 mm cannot be clearly distinguished; the non-recorded area is quite dark, the OD of the recorded image is quite low, and the pitch width is 1 s+m; Thickness 0.
A case where the line of the 3 m layer could not be clearly distinguished or a case where the non-recorded area and the recorded image could not be distinguished was rated as "×".

(4) Straight line transmittance was measured using a 323-type Hitachi self-recording spectrophotometer (manufactured by Hitachi, Ltd.), 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.

(5) Recording operability: When recording under conditions of 35°C and 85% RH, printing is not possible due to close contact between the recording material and the printer roller, etc. was set as 0.

(1 sect @) -1 Juji.　00

Claims (1)

[Claims] A recording material having an ink retaining layer and an ink permeable layer, characterized in that powder is dispersed in the ink permeable layer.