JPH10272836A - Ink jet recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink jet recording material, in the portion printed with which no crack develops even when a printing is performed in pigment ink by a method wherein a photosensitive ink receiving layer, which is mainly made of an uncured water-soluble photosensitive resin and the contact angle of which to a distilled water is a specified value, is provided through an ink solvent absorbing auxiliary layer onto a base material. SOLUTION: In this material, a photosensitive ink receiving layer is formed on a base material so as to cure the ink receiving layer after being recorded with ink in order to improve the water resistance of the layer. The photosensitive ink receiving layer, which is mainly made of an uncured water-soluble photosensitive resin and the contact angle of which to a distilled water is below 50 deg., is formed on a base material. In addition, an ink solvent absorbing auxiliary layer, the contact angle of which to a distilled water is 50-70 deg., is provided between the base material and the photosensitive ink receiving layer. Thus, the portion printed in pigment ink is prevented from cracking. The ink solvent absorbing auxiliary layer used is mainly made of polyvinyl acetal or polyester resin. Further, as the photosensitive ink receiving layer, a photocrossilinking type layer is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording material which has excellent water resistance after recording and which prevents a printed portion from cracking even when printed with a pigment ink.

[0002]

2. Description of the Related Art Dye inks containing water as a main component have conventionally been used as inks for ink-jet recording, and polyhydric alcohols have been used for preventing clogging of ink passages and ink discharge ports of the apparatus and improving discharge stability. Is generally added, and therefore, most recording materials mainly include a water-soluble resin as an ink receiving layer (Japanese Patent Application Laid-Open Nos. 61-188181 and 3-28138).
No. 4, etc.).

However, in recent years, the colorization of the ink jet recording method has been further advanced, and the ink jet recording method has been used for displays such as posters and signboards and for presentations. In this case, it is necessary that the ink receiving layer has water resistance such that it is not damaged by the weather, humidity, etc., and even if it is touched by wet or sweaty hands.

In view of this point, as an ink jet recording material suitable for outdoor display, a photosensitive ink receiving layer mainly composed of an uncured water-soluble photosensitive resin is formed on a substrate, and the ink receiving layer is formed after ink recording. A technique to achieve improvement in water resistance by curing is disclosed (JP-A-9-7104).
No. 1).

In addition, dye inks containing a water-soluble dye have low light resistance, so that when a display material using the dye ink is used for outdoor display, there is a disadvantage that the image area is easily faded. Pigment inks have no such drawbacks,
It is understood that the light fastness is remarkably improved. Therefore, when the display object is used as an outdoor display, it can be estimated that printing should be performed on the recording material described in the above publication using a pigment ink.

[0006]

However, when printing with a pigment ink is performed on the recording material described in the above-mentioned publication, the photosensitive ink-receiving layer swells by absorbing the solvent of the pigment ink, As a result that the printed portion made of the pigment remaining on the surface cannot follow the swelling, a new problem arises in that the printed portion is cracked.

Accordingly, an object of the present invention is to provide an ink jet recording material which is excellent in water resistance after recording and does not crack the printed portion even when printed with pigment ink.

[0008]

According to the ink jet recording material of the present invention which solves the above-mentioned problems, a contact angle of distilled water mainly composed of an uncured water-soluble photosensitive resin on a substrate is 50 or less.
A photosensitive ink-receiving layer having a contact angle of less than 50 degrees with distilled water between the substrate and the photosensitive ink-receiving layer.
It is characterized by having an ink solvent absorption auxiliary layer having a temperature of 70 to 70 degrees.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ink jet recording material of the present invention will be described below.

[0010] First, the layer structure has a photosensitive ink receiving layer having a contact angle of less than 50 degrees with distilled water mainly composed of an uncured water-soluble photosensitive resin on a base material. The contact angle with distilled water between the photosensitive ink receiving layer and the photosensitive ink receiving layer is 50 to 50.
It has an ink solvent absorption auxiliary layer at 70 degrees.

As the substrate, for example, a plastic film composed of polyester, polycarbonate, cellulose acetate, polyimide, polyethylene, polystyrene, polypropylene, polyvinyl chloride, polyvinyl alcohol, etc., as well as Western paper, Japanese paper, cloth and the like can be used.
When used as a transmissive material, it is preferable to use a substantially transparent plastic film. Here, “substantially transparent” means transparency enough to allow the printed portion to be seen through the base material, and there is no particular limitation on the thickness of the base material, and it can be appropriately selected according to the intended use. Usually 5-500
Those having a range of μm are used.

[0012] The ink solvent absorption auxiliary layer provided on the base material is used when the photosensitive ink receiving layer is printed with a pigment ink containing carbon black or the like as a main component and dispersed in a solvent. This is a layer for reducing the amount of solvent absorption by itself, suppressing swelling due to solvent absorption as much as possible, and preventing the occurrence of cracks in the printed portion.

[0013] Specifically, the resin is mainly composed of a resin having a contact angle of 50 to 70 degrees with distilled water when formed into a coating film. When the angle is less than 50 degrees, the ink solvent absorption auxiliary layer swells more than necessary, and the printed portion cannot follow the ink layer, causing cracks. When the angle exceeds 70 degrees, the solvent absorption aid of the photosensitive ink receiving layer is achieved. Because it is gone.

As such a resin, there are a polyvinyl resin, a polyester resin and the like, and it is particularly preferable that the resin is mainly composed of a polyvinyl acetal or a polyester resin.

In order to adjust the contact angle, an acid, salt or ester of carboxylic acid, sulfonic acid and phosphoric acid, a tertiary amine, a quaternary ammonium salt, and a hydrophilic group such as a hydroxyl group are introduced into the resin. Do it like this.

In addition, the ink solvent absorption auxiliary layer contains a pigment, an antioxidant, an ultraviolet absorber, a surfactant, a pH regulator and the like for preventing blocking, improving writability or imparting concealing properties. It does not matter if the pigment is silica, clay, smectite, mica, talc, titanium oxide, zinc oxide, calcium carbonate, barium sulfate,
Examples thereof include inorganic pigments such as aluminum oxide, and organic pigments such as acryl, silicone, cellulose, and polystyrene. The mixing weight ratio between the resin and the pigment is usually 10,000: 1 to 1: 2.
Is appropriate. The thickness is in the range of 1 to 50 μm, preferably 2 to 20 μm. If the thickness is less than 1 μm, the photosensitive ink-receiving layer itself does not play a role in assisting the solvent absorption, and if it exceeds 50 μm, it is not economical.

Next, the photosensitive ink receiving layer provided on the ink solvent absorption assisting layer is water-soluble in an uncured state and has poor water resistance, but the cured coating film has excellent water resistance.

Such a photosensitive ink receiving layer is formed in an uncured state mainly of a water-soluble photosensitive resin which undergoes a curing reaction when irradiated with actinic rays such as visible rays and ultraviolet rays. That is, it is composed of a resin that is water-soluble before curing, becomes substantially water-insoluble after curing, has hydrophilicity, and can maintain ink receptivity including ink absorbability and ink fixability. As the water-soluble photosensitive resin, a photo-crosslinking type, a photo-decomposition type, a photo-depolymerization type, a photo-modified type, a photo-polymerization type, etc. can be used, and the photo-crosslinking type is particularly preferable. This is because sufficient curing can be obtained without causing oxygen damage and other curing-related problems found in radical polymerization using a photopolymerization initiator.

As the water-soluble photo-crosslinkable photosensitive resin,
The photodimerization type and the diazo type are preferable in terms of handling, and among the photodimerization types, those in which a cinnamoyl group, a stilbazolium group, or a styrylquinolium group is introduced are more preferable in terms of water resistance and ink absorption. Materials in which the group is not introduced into the resin, but cross-link like a diazo type resin, often react with functional groups as needed because the coating film often becomes brittle when cured alone. It is preferable to mix a hydrophilic resin.

Such hydrophilic resins include, for example, starch, gelatin, casein, gum arabic, sodium alginate, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyvinyl alcohol, polyurethane, polyethylene glycol, polyethylene oxide, poly (meth)
A resin such as acrylic acid, a water-soluble polyester, or polyacrylamide, or a copolymer or a modified product thereof is at least one.
A mixture of more than one type is included. In addition, even if the photosensitive group is introduced into the resin, the hydrophilic resin can be added as long as the characteristics of the ink receiving layer intended in the present invention are not impaired. The thickness is 0.5-7 μm,
Preferably it is in the range of 1 to 4 μm. If the thickness is less than 0.5 μm, the water resistance after image formation and curing is insufficient, and
If the thickness is more than μm, cracks are likely to occur in the printed portion.

In addition to the water-soluble photosensitive resin, pigments for preventing blocking, improving writability or imparting hiding properties, other antioxidants, ultraviolet absorbers, surfactants, p
It may be added with an H regulator or the like, and pigments such as silica, clay, smectite, mica, talc,
Inorganic pigments such as titanium oxide, zinc oxide, calcium carbonate, barium sulfate, aluminum oxide, acrylic, silicone,
Organic pigments such as cellulose and polystyrene, and the like,
The mixing weight ratio of the resin and the pigment is usually 10,000: 1 to 1
1: 2.

In order to produce the ink jet recording material of the present invention, a resin or the like constituting the ink solvent absorption auxiliary layer is dissolved or dispersed in a suitable solvent on a base material to form a coating solution, which is prepared by using a roll, bar, air knife, or the like. It can be formed by applying by a known coating method such as spraying, drying and forming, and then applying a resin or the like constituting the photosensitive ink-receiving layer by the same method and drying it. The layer may be provided on one side or both sides of the substrate, and when provided on only one side, the back side is provided on the opposite side to prevent curling, or to improve slipperiness and transportability. A coat layer can be provided.

A display having excellent water resistance can be obtained by the ink-jet recording material of the present invention. However, when an image is formed with a dye ink, discoloration of a printed portion occurs due to low light resistance of the ink itself. There is. Therefore, it is useful to add an ultraviolet absorber to the base material or the back coat layer. Particularly when the ink receiving layer is provided on one side of the base material, mirror image (reverse image) printing is performed, and If the printed portion is viewed through the back coat layer, the low light resistance of the recording ink itself can be compensated, and this is effective when the display object is used outdoors.

Further, if an ultraviolet absorber is added to the base material or the back coat layer and the photosensitive ink receiving layer is stored with the light receiving layer opposite (downward) to the light source, the base material or the back coat layer can be used as the photosensitive ink receiving layer. It serves as a protective layer for the layer and can prevent a curing reaction (fog) before exposure. In the case of storing in a roll form, it is preferable that the photosensitive ink receiving layer side is stored in an inner wrap, so that fogging of the photosensitive agent can be prevented and the recording performance is not adversely affected.

After recording on the photosensitive ink-receiving layer of such an ink-jet recording material by an ink-jet printer, the photosensitive ink-receiving layer is exposed to ultraviolet light, visible light, infrared light, far infrared light, alpha ray, beta ray, gamma ray, X ray, etc. The photosensitive material is cured by irradiating (exposing) a required amount of actinic rays necessary for a curing reaction. Exposure can be performed using an artificial light source, or can be performed by exposing to direct sunlight or the like after recording. After recording in this way, by curing the photosensitive ink receiving layer,
A display having high water resistance and excellent fixability of a recorded image can be obtained.

[0026]

The present invention will be described in more detail with reference to the following examples.

Example 1 Polyvinyl acetal (Eslek KX-1: Sekisui Chemical Co., Ltd.) on a 100 μm-thick polyester film (Lumilar Q81: Toray Industries, Inc.)
An ink solvent absorption auxiliary layer coating solution containing 100 parts by weight is applied by a bar coater so that the dry thickness becomes 5 μm, and dried at 100 ° C. for 5 minutes by a drier. Then, one drop of distilled water was dropped on the ink solvent absorption auxiliary layer, and the contact angle after 1 minute was measured using a contact angle measuring device (GI-1000: Elma). As a result, it was 57 to 59 degrees.

2 parts by weight of polyvinyl alcohol (Gohsenol GL-05: Nippon Synthetic Chemical Industry Co., Ltd.), 8 parts by weight of a polyvinyl alcohol derivative (SSP-H13: Toyo Gosei Co., Ltd.) into which a stilbazolium group (SBQ group) was introduced, A coating liquid consisting of 115 parts by weight of water has a dry thickness of 2 μm.
m with a bar coater and 10 in a dryer.
After drying at 0 ° C. for 5 minutes, an ink jet recording material was obtained. The contact angle on the photosensitive ink receiving layer was measured in the same manner as described above. As a result, it was 26 to 28 degrees.

Example 2 The same as Example 1 except that the polyvinyl acetal (Eslek KX-1: Sekisui Chemical Co., Ltd.) of Example 1 was replaced with a polyester resin (Peslezine A-513D: Takamatsu Yushi Kagaku). Thus, an ink solvent absorption auxiliary layer was formed. In this case, the contact angle on the ink solvent absorption auxiliary layer was 64-67 degrees. A photosensitive ink receiving layer was also formed in the same manner as in Example 1.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the coating solution for the ink solvent absorption auxiliary layer was applied to a dry thickness of 7 μm, and the photosensitive ink receiving layer was not laminated thereon. An ink jet recording material was obtained in the same manner as in Example 1.

[Comparative Example 2] Same as Example 1 except that the ink solvent absorption auxiliary layer of Example 1 was not provided and the photosensitive ink receiving layer was applied directly on the substrate so that the dry thickness became 7 μm. Thus, an ink jet recording material was obtained.

Comparative Example 3 An ink jet recording material was obtained in the same manner as in Example 1 except that the coating liquid for the photosensitive ink receiving layer of Example 1 was applied so as to have a dry thickness of about 15 μm.

[Comparative Example 4] The coating solution for the ink solvent absorption auxiliary layer in Example 1 was prepared using polyvinyl alcohol (Gohsenol GL).
-05: Nippon Synthetic Chemical Industry Co., Ltd.) An ink jet recording material was obtained in the same manner as in Example 1 except that the coating liquid was 10 parts by weight and water was 115 parts by weight.

The ink-jet recording materials obtained in Examples 1 and 2 and Comparative Examples 1 to 3 were printed with a dye ink and a pigment ink using an ink-jet printer (PR101 / J180: NEC), and then printed in Examples and Comparative Examples 2 to 4. For the material of the above, 300 mJ / cm ²
Was exposed to obtain a display. The resulting display was evaluated for dye ink print characteristics, pigment ink print characteristics, water resistance, and ink fixability. Table 1 shows the results.

[0035]

[Table 1]

(Dye ink printing characteristics): Solid printing and fine line printing are performed on the ink jet recording material with the dye ink.
When the solid print portion was rubbed with a finger after a certain period of time, the transfer of the ink and the bleeding of the fine line print portion by visual judgment did not occur and those that did not substantially occur are indicated by `` ◎ '' and `` ○ '' respectively, Those that were not dried or those that had bleeding were designated as "x".

(Pigment ink printing characteristics): Solid printing and fine line printing were performed on the ink jet recording material with pigment ink.
When a solid print portion was rubbed with a finger after a certain period of time, ink transfer, bleeding of the fine line print portion by visual judgment, and no cracks and substantially no cracks in the image forming portion in both the solid print portion and the fine line print portion Those which did not occur are indicated by “◎” and “○”, respectively, and those that were not dried, those that had bleeding, or those that had cracks in the image forming portion were marked “X”.

(Water resistance): When the entire surface is immersed in water and the ink-receiving layer is rubbed, the ink-receiving layer is not eluted or peeled off, and is not substantially eluted or peeled off. Are indicated by “◎” and “○”, respectively, and those that have been eluted or peeled are designated as “x”.

(Ink fixability): After printing with a printer,
The entire surface is immersed in water at about 20 ° C., and after standing for 2 hours, the printed image is visually evaluated. "◎" indicates that the image has no change and that the image has substantially no change
And "O", those which were considerably faded but the image could be discriminated were marked with "△", those where the image could not be discriminated were marked "x", and those which could not be measured without water resistance were marked "impossible".

Example 3 40 parts by weight of a polyester resin (Vylon 200: Toyobo Co., Ltd.) and an ultraviolet absorber (UVINAL: ISP) were provided on the surface opposite to the ink receiving surface of the ink jet recording material obtained in Example 1. The coating liquid comprising 8 parts by weight, 70 parts by weight of methyl ethyl ketone, 70 parts by weight of toluene, and 20 parts by weight of anone has a thickness of 3 μm after drying.
Was applied with a bar coater and dried to produce an ink jet recording material provided with a back coat layer containing an ultraviolet absorbent.

The ink jet recording material obtained in Example 2 was added to the ink jet printer (B
After printing with JC600J (Canon), exposure was performed at 300 mJ / cm ² using a high-pressure mercury lamp, and the resulting display was subjected to a light resistance test with a fade meter FAL-3 (Suga Test Instruments Co., Ltd.). In the case without the back coat layer (Example 1), about 10% of the initial density was faded in 3 hours, whereas in the case of Example 4 in which the ultraviolet light shielding layer was used, the fade was 5% or less even in 24 hours.

As shown in Table 1, Example 1 has good overall printing characteristics and water resistance. Furthermore, in Example 2, the fading of the printed image after irradiation with ultraviolet light was small because the back coat layer contained an ultraviolet absorbent.

On the other hand, in Comparative Example 1, although the printing characteristics of the pigment ink were improved, the receiving performance of the dye ink was slightly lowered, and the water resistance and the ink fixability were not satisfactory. In Comparative Examples 2 and 3, the image area cracked during printing of the pigment ink. It is considered that in Comparative Example 3, the effect of the lower layer could not be obtained because the upper layer was too thick. Comparative Example 4
Was poor in pigment ink receiving performance, water resistance, and image fixability because a water-soluble resin was used for the lower layer.

[0044]

The ink jet recording material of the present invention has a specific photosensitive ink receiving layer mainly composed of an uncured water-soluble photosensitive resin on a base material, and the base material and the photosensitive ink receiving layer. By having a specific ink solvent absorption auxiliary layer between the layer and the layer, if the ink receiving layer is cured, especially after printing with pigment ink, the display has high water resistance and does not cause cracks in the printed portion. Things are obtained. This is useful as an outdoor display material.

Claims (1)

[Claims] 1. A substrate comprising a photosensitive ink receiving layer mainly composed of an uncured water-soluble photosensitive resin and having a contact angle of distilled water of less than 50 degrees, said substrate and said photosensitive ink. An ink jet recording material having an ink solvent absorption auxiliary layer having a contact angle of 50 to 70 degrees with distilled water between the receiving layer and the receiving layer.