JP3112645B2 - Inkjet recording materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium for recording using an aqueous ink, and more particularly to a recording medium suitable for full-color ink jet recording using a plastic film as a base material.

[0002]

2. Description of the Related Art An ink jet recording method is a method in which an aqueous ink is ejected as fine particles from a recording head by thermal energy or physical vibration energy to form an image or a character on the surface of a recording material. Compared to dot impact printers, which have been the mainstream of printers until now,
Due to the fact that high-speed printing is possible, the noise at the time of printing is small, the apparatus is relatively simple and low-cost, and full-color printing is easy, it is rapidly spreading. Particularly in recent years, printing by the ink jet recording method has also shifted to full color printing because it is visually clear and easy to see. Further, in addition to printers, applications to plotters, facsimile machines, copiers, and the like have been actively performed.

[0003] Ink-jet recording materials include plain paper and specialty paper that has been required to have good ink-jet recording characteristics.
There is an OHP film based on a transparent plastic film. In addition, as an inkjet recording material using the transparent plastic film as a base material, a label,
There are display materials such as stickers, illuminated signboards and color signboards, and are used for a wide range of applications.

In general, the image quality required for an ink jet recording material is as follows: 1) It has excellent absorption capacity for inks of four colors, yellow, magenta, cyan, and black, and does not cause uneven absorption (density unevenness) or cissing; There are the following: uniform full-color reproduction can be achieved; 2) each dot does not spread due to ink bleeding; a sharp and clear recorded image can be obtained; and 3) excellent ink drying properties.

Further, in the OHP film, in addition to the above-described elements, it is an essential condition that the projecting property of an image is excellent. In addition, in the case of materials such as labels and stickers that are sweaty or greasy to be directly touched by hands, or display materials for outdoor use such as illuminated signs and color signboards, in addition to the above-described elements, Further, water resistance is required. However, when the base material of the recording material is a plastic film, since the plastic film is hydrophobic, the ink-absorbing property of the ink-jet recording method using an aqueous ink is inferior, and the ink cohesion phenomenon (in the form of beads).
As a result, a high-quality recorded image could not be obtained.

[0006] Therefore, in order to impart ink jet aptitude, it is common practice to apply an ink receiving layer made of a water-absorbing resin or a water-soluble resin on a plastic substrate (JP-A-60-220750). No.). Such water-absorbing resin or water-soluble resin, for example, polyvinyl alcohol, gelatin, carboxymethylcellulose, polyvinylpyrrolidone, polyethylene oxide,
Polyacrylic acid, acrylamide, sodium acrylate,
And polyethyleneimine and the like are used.

However, when a normal water-absorbing resin is used for the ink receiving layer, the ink absorbing property is good,
It has drawbacks such as easy bleeding, easy ink unevenness, and mixed color bleeding. In addition, if water or sweat adheres, the recorded image may flow, become sticky, cause blocking, etc. Problem occurred. Then, a method of using a cellulose-reactive resin to make it water-resistant (Japanese Patent Publication Nos. 5-88678 and 6-427) has been proposed. However, in the case of this method, even if a small amount of the cellulose-reactive resin is added, no great effect is recognized, and there is a drawback that the image quality and the ink absorbability are reduced when the added amount is increased.

On the other hand, it has been proposed to use a porous inorganic material such as colloidal silica or alumina sol in place of the cellulose-reactive resin (JP-A-57-14091, JP-A-61-19389, and JP-A-Hei. 1-95091
JP, 6-297832, JP-B-3-249
06 publication). However, although water resistance is obtained by this method, the obtained image receiving layer is hard and brittle, so that there is a new disadvantage that a scratch is easily generated by a feed roll or the like during printing by a printer. OHP
In the case of a film, since a porous inorganic material is used for the ink receiving layer, there is also a disadvantage that light transmittance is reduced, and a projected image is fogged or colored.

[0009] Furthermore, ethylene oxide
By applying an ink receiving layer composed of a mixture of an alkylene oxide copolymer and a polymer having a softening point of 70 ° C. or higher, it is possible to prevent the occurrence of image unevenness and color mixing bleeding due to ink bleeding, and increase of bleeding with time, and the like. A method for improving the drying property (Japanese Patent Application Laid-Open No. 7-9557) has been proposed.

[0010] However, even with this method, the flow of recorded images caused by direct contact with sweat or water,
And water resistance for preventing stickiness and blocking could not be provided. Therefore, when the plastic film is used as the base material in this manner, the image quality,
It was extremely difficult to satisfy all the ink drying properties and water resistance.

[0011]

The inventors of the present invention have conducted intensive studies on the above-mentioned problems, and as a result, as a main component of an ink receiving layer provided on a plastic film, a reaction product of a polyalkylene oxide and an isocyanate has been obtained.
By mixing the cellulose ester resin of water-insoluble at a constant rate, time of image recording with aqueous ink, can be obtained a uniform image causing no bleeding density unevenness and image, and is excellent in ink drying properties The inventors have found that they have excellent water resistance, and have reached the present invention. Accordingly, an object of the present invention is to provide an ink jet recording material that can simultaneously achieve both water resistance and good image quality when performing image recording using an aqueous ink.

[0012]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
In the ink-jet recording material comprising at least one layer of the ink-receiving layer is provided on the substrate, wherein the ink-receiving layer is a reaction product of polyalkylene oxides with isocyanates, and, together containing a cellulose ester resin of the water-insoluble, wherein the poly Isocyanates of alkylene oxides
Of reactant and water-insoluble cellulose ester resin
This has been achieved by an ink jet recording material characterized in that the ratio is between 90/10 and 10/90 .

The substrate used in the present invention includes:
It can be appropriately selected from well-known materials conventionally used as a base material, including a plastic film. Examples of the plastic film include, for example, synthetic resin films such as polyester, polypropylene, polycarbonate, cellulose acetate, and polyimide. Among these, a polyester film having a thickness of 6 to 300 μm is particularly preferable in terms of properties and price. .

Next, the ink receiving layer in the recording material of the present invention will be described in detail. Examples of the polyalkylene oxide used in the ink receiving layer of the present invention include homopolymers and copolymers of polyethylene oxide and polypropylene oxide, and the average molecular weight can be appropriately selected.

The isocyanate used in the present invention can be appropriately selected from known isocyanates containing at least one isocyanate group.
Specific examples thereof include propyl isocyanate, hexyl isocyanate, hexamethylene diisocyanate,
Diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate,
1-methyl-2,4,6-triisocyanate, and
And naphthalene-1,3,7-triisocyanate. In the present invention, among these, those containing two or more isocyanate groups are preferable.

[0016] As cell <br/> loin ester resin of water-insoluble used in the present invention, for example, cellulose acetate, cellulose propionate, cellulose acetate butyrate, cellulose acetate isobutyrate, cellulose acetate propionate, cellulose Nitrate, hydroxypropyl methylcellulose phthalate, derivatives thereof, and the like can be given. These may be used alone or in combination of two or more.

The isocyanate reactant and the cellulose ester of the water-insoluble polyalkylene oxides in the present invention
The mixing ratio with the resin is preferably from 90/10 to 10/90. If the amount of the isocyanate reactant of the polyalkylene oxide is too large, the water resistance is lowered and the ink drying property is deteriorated. Further, the water-insoluble cellulose ester trees
If the amount of the fat is too large, the water resistance is excessively improved, so that the ink absorbing ability and the image quality are deteriorated.

When polyalkylene oxide is used alone as the ink receiving layer, the ink absorbency and image quality are improved, but water resistance is not obtained and ink bleeding occurs. In addition, when a reaction product of a polyalkylene oxide and an isocyanate is used alone, the effect of improving water resistance is recognized, but the ink absorbency and image quality are reduced.

In the present invention, in order to further improve the recording characteristics of the ink jet, an inorganic and / or organic pigment can be appropriately added to the ink receiving layer. As inorganic pigments, silica, alumina, titanium oxide, zinc oxide, zinc sulfide, kaolin, clay, talc, diatomaceous earth, zeolite, mica, calcium carbonate, calcium silicate, aluminum silicate, magnesium silicate, barium sulfate, etc. No. Examples of the organic pigment include fine particles of polymethyl methacrylate, polystyrene, polyvinylidene chloride, and polycarbonate. These may be used alone or in combination of two or more.

Further, if necessary, a water-proofing agent, an antistatic agent, an ultraviolet absorber, a coloring dye and a pigment and the like can be added and used. In addition, the base material is transparent,
In addition, when used for applications requiring transparency, it is necessary to add a pigment within a range that does not lose transparency.

[0021] As a method for forming the ink-receiving layer of the present invention, the reaction product of a polyalkylene oxide and an isocyanate, a composition comprising a mixture of the mixture of cellulose ester resin of the water-insoluble and coating liquid, bar coating, air knife Known coating methods such as a coat, a curtain coat, a gravure coat, a roll coat, and a spray coat can be used.

The ink receiving layer has a coating layer thickness of 0.1 to 2
Preferably, it is provided in a range of 5 μm. When the thickness of the coating layer exceeds 0.1 μm, the ink absorbency is insufficient, and when the thickness of the coating layer exceeds 25 μm, the ink absorption capacity is not improved as compared with the case of 25 μm. It is uneconomical.

The ink-receiving layer of the present invention may be formed by applying the same coating liquid in multiple layers or by changing the composition ratio of the coating liquid in multiple layers. It is necessary to satisfy the requirements of When the ink receiving layer is difficult to adhere to the substrate, an adhesive layer can be provided between the ink receiving layer and the substrate. Examples of the adhesive used herein include polyester, vinyl chloride, vinylidene chloride, ethylene / vinyl acetate, and known adhesives such as a copolymer of styrene and acrylic acid or a derivative thereof.
At least one kind can be appropriately selected.

Examples of the solvent for dissolving the material for the ink receiving layer, which is used when preparing the coating liquid of the present invention, include, for example,
Examples include toluene, xylene, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, dichloroethylene, trichloroethylene, methyl ethyl ketone, methyl isobutyl ketone, acetone, methanol, ethanol, isopropanol, cyclohexanone, and dimethylformamide. These may be used alone or in combination of two or more.

In the present invention, an ink absorbing layer made of a water-absorbing resin or a water-soluble resin may be provided between the ink receiving layer and the substrate or the adhesive layer in order to improve the ink absorbing property. Examples of the water-absorbing resin or the water-soluble resin include polyvinyl alcohol, polyvinyl acetal, gelatin, starch, casein, gum arabic,
Methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, polyvinylpyrrolidone, polyethylene oxide, polyacrylic acid or a copolymer thereof,
Polymethacrylic acid or a copolymer thereof, acrylamide,
Examples thereof include sodium acrylate and polyethylene imine, and a cationic resin can also be used as a fixing agent for the ink. These may be used alone or in combination of two or more.

The recording material of the present invention is a recording material which is excellent in image quality, ink drying property and water resistance and is suitable for ink-jet recording, and can be used as a recording material for ink-jet printers, ink-jet plotters, water-based pen plotters and the like. Can be. In particular, when a transparent substrate such as a plastic film is used, it can be used as a recording material for an overhead projector (OPH), an illuminated panel, a sticker, a label, a drawing film, a high gloss film, and the like.

[0027]

Jet recording material of the embodiment of the present invention is the reaction product obtained by reacting a polyalkylene oxide with an isocyanate and water-insoluble cellulose ester trees
The fat is dissolved in a solvent such as toluene, and a pigment or other additive is appropriately added to prepare a coating liquid, and the obtained coating liquid is applied to at least one surface of the substrate and dried. Can be In this case, the coating solution of the same component may be applied twice or more, or the composition may be changed to perform multi-layer application.

[0028]

According to the ink jet recording material of the present invention, a polyalkylene oxide resin having high affinity for water and excellent absorption is used for the ink receiving layer.
Not only the water-based ink has sufficient absorptivity, but also the hydroxyl groups of the polyalkylene oxide resin are partially thermally crosslinked with isocyanate to improve water resistance, improve uniform ink absorption without density unevenness, and prevent cissing. Can be measured. Further, the crosslinked product of the polyalkylene oxide resin and isocyanate water-insoluble cellulose et
Because of the addition of stell resin , the water resistance is further improved,
Since it is possible to prevent image bleeding and to control the size of dots, it is possible to have both good image quality and water resistance, thereby expanding the range of use of a quick and inexpensive inkjet printer.

[0029]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.
Unless otherwise specified, “%” described below means “% by weight”.

Preparation of Ink Receiving Layer Component and Ink Absorbing Layer Component: Ink receiving layer component Polyethylene oxide (Paogen PP-15: trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 70
Parts, fatty acid isocyanate-based prepolymer (Takenate D-177: trade name, manufactured by Takeda Pharmaceutical Co., Ltd.), 1 part, hydroxypropyl methylcellulose phthalate (HP-5
0: 30 parts of Shin-Etsu Chemical Co., Ltd.), toluene 5
0 parts, methyl ethyl ketone 10 parts.

Ink receiving layer components2. Polyethylene oxide (Aqua Coke: trade name manufactured by Sumitomo Seika Co., Ltd.) 70
Parts, 1 part of the same fatty acid isocyanate-based prepolymer as used in the ink receiving layer component 1, 30 parts of hydroxypropylmethylcellulose phthalate, 50 parts of toluene, and 10 parts of methyl ethyl ketone.

Ink receiving layer component 3. Crosslinked isocyanate of polyethylene oxide (Aquaprene L-173:
70 parts of Meisei Chemical Co., Ltd., 70 parts of hydroxypropyl methylcellulose phthalate, 50 parts of toluene
Parts, methyl ethyl ketone 10 parts.

Ink receiving layer component 4. 70 parts of polyethylene oxide (Paogen PP-15: trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 30 parts of hydroxypropyl methylcellulose phthalate, 50 parts of toluene, 10 parts of methyl ethyl ketone.

Ink receiving layer components5. 1 part of a fatty acid isocyanate-based prepolymer (Takenate D-177: trade name, manufactured by Takeda Pharmaceutical Co., Ltd.), 30 parts of hydroxypropylmethylcellulose phthalate, 50 parts of toluene, 10 parts of methyl ethyl ketone.

Ink receiving layer component 6. 70 parts of polyethylene oxide (Paogen PP-15: trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 1 part of the same fatty acid isocyanate prepolymer as used in ink receiving layer component 1, and 5 parts of toluene
0 parts, methyl ethyl ketone 10 parts.

Ink Absorbing Layer Components Polyvinyl alcohol (PVA117: trade name, manufactured by Kuraray Co., Ltd.) 50
Parts, polyvinylpyrrolidone (K-90: trade name, manufactured by ISP Corporation), 30 parts, cationic polymer (Saftomer ST-2100, trade name, manufactured by Mitsubishi Chemical Corporation) 20
Parts, methanol 50 parts, ethyl cellosolve 10 parts.

Embodiment 1 Pre-adhesion treated,
A 100 μm-thick polyethylene terephthalate film (Cosmoshine A-1100: trade name, manufactured by Toyobo Co., Ltd.) was used as a base material, and an ink receiving component 1 was formed thereon.
Was applied using a bar coating method so that the thickness of the coating layer after drying was 10 μm, and then applied at 150 ° C.
After drying for 3 minutes, an ink jet recording material was obtained.

Embodiment 2 FIG. An ink jet recording material was obtained in exactly the same manner as in Example 1 except that the ink receiving component 2 was used instead of the ink receiving component 1.

Embodiment 3 FIG. An ink jet recording material was obtained in exactly the same manner as in Example 1, except that the ink receiving component 3 was used instead of the ink receiving component 1.

Embodiment 4 FIG. Pre-adhesion treated,
A 100 μm-thick polyethylene terephthalate film (Cosmoshine A-1100: trade name, manufactured by Toyobo Co., Ltd.) was used as a base material, and an ink absorbing component 1 was formed thereon.
Was applied using a bar coating method so that the thickness of the coating layer after drying was 10 μm, and then applied at 150 ° C.
Dried for 3 minutes to form an ink absorbing layer, and on top of that,
The coating liquid of the ink receiving component 1 was applied using a bar coating method so that the thickness of the coating layer after drying was 3 μm, and then dried at 150 ° C. for 3 minutes to obtain an ink jet recording material. .

Embodiment 5 FIG. An ink jet recording material was obtained in exactly the same manner as in Example 4 except that ink receiving component 2 was used instead of ink receiving component 1.

Embodiment 6 FIG. An ink jet recording material was obtained in exactly the same manner as in Example 4 except that the ink receiving component 3 was used instead of the ink receiving component 1.

Comparative Example 1 An ink jet recording material was obtained in exactly the same manner as in Example 1 except that the ink receiving component 4 was used instead of the ink receiving component 1.

Comparative Example 2 An ink jet recording material was obtained in exactly the same manner as in Example 1, except that the ink receiving component 5 was used instead of the ink receiving component 1.

Comparative Example 3 An ink jet recording material was obtained in exactly the same manner as in Example 1 except that the ink receiving component 6 was used instead of the ink receiving component 1.

The recording materials produced in the above Examples and Comparative Examples were measured and evaluated by the following test methods, and the evaluation results are as shown in Table 1.

[Table 1]

From Table 1, it was proved that all the ink jet recording materials of Examples 1 to 6 of the present invention were excellent in ink drying property and water resistance. In contrast, in Comparative Example 3 does not use the cellulose <br/> scan ester resin of Comparative Example 1 and a water-insoluble without using isocyanate, poor ink drying properties, also water resistance is slightly inferior. In Comparative Example 2 in which no polyethylene oxide was used, although the water resistance was good,
It was confirmed that the image quality and the ink drying property were inferior.

1. The image quality was evaluated for bleeding, bleeding, density unevenness, dot size and shape when recorded by an inkjet printer (BJC-660J: a product manufactured by Canon Inc.). Very good ◎ Good ○ Slightly inferior △ Ink bleeding, repelling, uneven density ×

2. The ink drying property was evaluated by the time required for the ink to completely dry when solid printing was performed by an inkjet printer. Less than 5 minutes ◎ More than 5 minutes and less than 10 minutes ○ More than 10 minutes and less than 30 minutes △ More than 30 minutes ×

3. The water resistance was evaluated by rubbing the image receiving layer with a cotton swab soaked in water and measuring the number of times until the image receiving layer was peeled off. 50 times or more ◎ 20 to 49 times ○ 10 to 19 times △ 9 times or less ×

Continuation of the front page (72) Inventor Masahide Takano 1551 Higashidaira, Higashimatsuyama-shi, Saitama Nippon Paper Industries Image Engineering Center (56) References JP-A-61-32787 (JP, A) JP-A-60-248387 (JP) , A) JP-A-4-41289 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/00

Claims (2)

(57) [Claims] 1. A ink jet recording material comprising at least one layer of the ink-receiving layer is provided on the substrate, wherein the ink-receiving layer, the reaction product of polyalkylene oxide to isocyanates, and, of water-insoluble cellulose ester
Together containing Le resin, the polyalkylene oxide
Isocyanate Reactants and Water-Insoluble Cellulose Esters
Jet recording material mixing ratio of the Le resin is characterized this <br/> and 90 / 10-10 / 90. 2. The method according to claim 1, wherein the base material is a plastic film.
8. The ink jet recording material according to claim 1 .