JPH09156209A - Inkjet recording sheet - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a translucent inkjet recording sheet excellent in ink drying property, image quality and OHP projection property. Kind Code: A1 An inkjet recording sheet comprising a translucent substrate and at least one or more ink receiving layers provided thereon, wherein the ink receiving layer comprises (A) a polyvinyl acetal resin and / or a polyvinyl alcohol resin. When,
(B) at least one resin selected from the group of resins consisting of acryl, polyester, styrene acryl, ethylene / vinyl acetate, vinyl acetate / acryl, ethylene / vinyl acetate / acryl, ethylene / acryl, and polyethylene. An inkjet recording sheet comprising:

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet for recording using an aqueous ink, and more particularly, an overhead projector (hereinafter abbreviated as OHP) film, a film for an electric decoration panel, a sticker, a label, a drawing film,
The present invention relates to a recording material that can be used for high-gloss films and is suitable for full-color inkjet recording.

[0002]

2. Description of the Related Art An ink jet recording method is a method of forming an image or a character on a surface of a recording medium by ejecting a water-based ink as fine particles from a recording head by thermal energy or physical vibration energy. This method, compared to the dot impact printer that was the mainstream until now,
Capable of high-speed recording, low noise during recording, relatively simple device, and easy cost reduction,
Also, it is rapidly becoming popular because it is easy to make full color. In addition to printers, they are also being actively applied to plotters, facsimiles, copiers, and the like.

Conventionally, as a recording medium on which an image is formed by using the ink jet recording method, Japanese Patent Publication No. 3-26665 is known.
A recording paper having a coating layer made of a mixed system of finely divided silica and a water-soluble polyvinyl alcohol resin on a base paper as described in Japanese Patent Publication No. 3-25352. Saponification degree of cast coated paper is 50 ~
A glossy paper having a coating film composed of 90 mol% of polyvinyl alcohol resin and a crosslinking agent, or JP-A-60-22.
There is an OHP recording sheet in which a hydrophilic coating film made of a water-soluble polyvinyl alcohol having a saponification degree of 70 to 90 mol% is formed on a polyester film as described in Japanese Patent No. 0750.

[0004]

In recent years, with the improvement of the performance of ink jet recording apparatus such as speeding up of recording and multi-coloring, the ink jet recording sheet is more advanced in a wide range of the following points. Characteristics are required. (1) The ink absorption capacity is high and the ink drying property is excellent. (2) Good full-color recording characteristics such that the inks do not mix when the inks overlap. (3) The optical density of dots is high and there is no ink bleeding or unevenness. (4) The dot shape is close to a perfect circle, and its periphery is smooth,
High resolution. (5) It has excellent water resistance. (6) A recorded image having excellent translucency can be obtained.

Particularly, regarding the method of recording a translucent image,
As the recording speed increases, the image density increases, and the color increases, the deterioration of image quality due to defective ink fixing of the recording sheet becomes a serious problem. That is, since the translucent recording sheet uses a synthetic resin film as a base material, its recording surface does not have a porous structure as in the case of coated paper or plain paper, and the receiving surface provided on the surface of the base material. Since only the layer absorbs the ink, the drying ability of the ink is reduced. Therefore, especially in the case of color printing, color smear (boundary blur) due to color mixture occurs at the boundary between different colors or at the boundary where a large amount of ink adheres, such as when two single color inks are mixed. It had the drawback of being prone to occur.

Further, even if the ink has good dryness,
Since the minute ink droplets ejected from the printer are absorbed as they are without spreading on the ink receiving layer, the ink droplets become granular and irregularly connected on the surface of the ink receiving layer. A beading phenomenon occurs in which the recorded image appears to be uneven. This phenomenon reduces the sharpness of the image together with the above-mentioned color stain. Therefore, a translucent recording sheet having excellent performance such as ink drying property, beading, and boundary bleeding, which are important problems in inkjet recording, has not yet been obtained.

Therefore, as a result of diligent studies on a translucent recording sheet suitable for ink jet recording, the present inventors have found that extremely good results can be obtained by using a specific resin for the recording layer. Has reached the present invention. Therefore, an object of the present invention is to provide a translucent inkjet recording sheet suitable for full-color inkjet recording.

[0008]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
An ink jet recording sheet comprising at least one ink receiving layer provided on a translucent substrate, wherein the ink receiving layer comprises (A) a polyvinyl acetal resin and / or a polyvinyl alcohol resin, ) From at least one resin selected from the group of resins consisting of acrylic, polyester, styrene / acrylic, ethylene / vinyl acetate, vinyl acetate / acrylic, ethylene / vinyl acetate / acrylic, ethylene / acrylic, and polyethylene And an ink jet recording sheet.

As the translucent substrate used in the present invention, a conventionally known transparent substrate can be used. Examples of such a base material include synthetic resin films such as polyester, polypropylene, polycarbonate, cellulose triacetate, and polyimide. Among the above-mentioned base materials, a biaxially stretched polyester film is particularly preferable from the viewpoint of strength, heat resistance, dimensional stability and price. As the translucent base material, one having an arbitrary thickness of 6 to 300 μm can be used. It is also possible to provide an adhesive layer between the ink receiving layer and the substrate.

In the polyvinyl alcohol resin used in the present invention, the higher the degree of polymerization, the better the water resistance.
A polymerization degree of 500 to 3,500 is suitable. Further, the higher the saponification degree is, the better the ink absorbability is. Therefore, the saponification degree is preferably 70 to 90 mol%, and from the viewpoint of easy availability, it is particularly preferably 75 to 85 mol%.

The polyvinyl acetal resin is obtained by reacting (condensing) a polyvinyl alcohol resin and an aldehyde as raw materials by a known method to form an acetal. In this case, the degree of polymerization of the polyvinyl alcohol resin as a raw material is preferably 500 to 3,500, and the degree of saponification is preferably 70 to 90 mol%, and particularly preferably 75 to 85 mol%. .

Further, the aldehyde to be reacted is preferably an aromatic aldehyde such as benzaldehyde from the viewpoint of improving the water resistance of the resin. Furthermore, the preferable range of the degree of acetalization in the polyvinyl acetal resin is 3
It is ˜30 mol%, and particularly preferably 5 to 15 mol%. If the degree of acetalization is too low, the water resistance will be poor, and if the degree of acetalization is too high, the ink absorbency and fixability will be reduced.

The resin (B) used in the present invention is an acrylic resin, a polyester resin, a styrene / acrylic copolymer resin, an ethylene / vinyl acetate copolymer resin, a vinyl acetate / acrylic copolymer resin, an ethylene / vinyl acetate / acrylic 3 resin.
At least 1 selected from the group consisting of terpolymer resins, ethylene / acrylic copolymer resins, and polyethylene
Water-soluble and / or water-based fine particle dispersion resin.

In the present invention, by providing a recording layer comprising at least one layer in which the resin (A) and the resin (B) are mixed, a recording layer comprising only the resin (A) or the resin (B) is provided. Compared with the case, the boundary has no bleeding, the ink drying property is good, uniform ink absorbency and beading are less likely to occur, so that a high-quality image can be obtained. The mixing ratio of (A) resin and (B) resin is
Resin (B) is 3 to 3 to 50 parts by weight of resin (A).
It is preferably 50 parts by weight. Within the range of this ratio, the coating liquids of the same composition may be applied two or more times to form a multilayer, or the coating liquids of different compositions may be applied repeatedly to form a multilayer.

When the mixing ratio of the resin (B) in the ink receiving layer is less than 3% by weight of the resin, the ejected ink is difficult to spread, so that beading is likely to occur and the sharpness of the image is deteriorated. On the other hand, if it exceeds 50% by weight, the ink absorbing ability and the drying property are deteriorated, and the blurring of the boundary is likely to occur. Also, when selecting the (B) resin,
It is necessary to select in consideration of the winding suitability (blocking) for winding the recording sheet during manufacturing.

If necessary, an inorganic or organic pigment can be added to the ink receiving layer of the present invention. Examples of the inorganic pigment include silica, alumina, titanium oxide, zinc oxide, zinc sulfide, kaolin, clay, talc, diatomaceous earth, zeolite, mica, calcium carbonate, calcium silicate, magnesium silicate, barium sulfate. .

Examples of the organic pigment include fine particles of polymethylmethacrylate resin, polystyrene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polycarbonate resin, acrylic resin, polyester resin and the like. It is also possible to add a water-proofing agent, an antistatic agent, an ultraviolet absorber, a dye or pigment for coloring, etc. to the ink receiving layer of the present invention, and these various additives are used alone. Alternatively, they may be mixed and used.

In forming the ink receiving layer, a comma coat, a lip coat, a bar coat, an air knife coat,
Known coating methods such as curtain coating, gravure coating, roll coating and spray coating can be used. The coating thickness of the formed ink receiving layer was 0.1.
If it is less than μm, the ink absorbency is lowered, and it is not possible to obtain a recording having excellent image quality. In addition, since the ink absorption capacity increases as the coating thickness increases, the coating thickness may be determined according to the ink ejection amount of the printer.

When it is difficult for the ink receiving layer to adhere to the substrate, an adhesive layer may be provided between the ink receiving layer and the substrate. As the adhesive here, at least one kind may be appropriately selected from known adhesives such as polyester, vinyl chloride, vinylidene chloride, ethylene / vinyl acetate copolymer, and styrene / acrylic ester copolymer. it can. Further, a back coat layer may be provided on the opposite surface of the ink receiving layer for the purpose of imparting slipperiness, blocking prevention, curl prevention and the like.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The ink jet recording sheet of the present invention comprises, for example, 80 parts by weight of polyvinyl alcohol having a degree of polymerization of 2000 and a degree of saponification of 80 mol% and a degree of acetalization of 20 mol on a biaxially stretched polyester film. It can be easily obtained by applying an aqueous solution containing 20 parts by weight of polyvinyl acetal having a degree of polymerization of 2000 in% and providing an ink receiving layer having a thickness of 10 μm. Since the obtained ink jet recording sheet is translucent, it is suitably used as an OHP film, a drawing film, and the like.

[0021]

The ink jet recorded matter according to the present invention is
Since a high-quality color image can be easily obtained, the application range of the inkjet printer can be expanded more than ever.

[0022]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The amounts of chemicals added in Examples and Comparative Examples are parts by weight or% by weight unless otherwise specified.

Embodiment 1 FIG. As a translucent base material, a polyester film having a thickness of 100 μm which has been subjected to easy adhesion treatment in advance (trade name: Cosmoshine A-1, manufactured by Toyobo Co., Ltd.)
100) was coated with a coating composition having the following composition so as to have a thickness after drying of 5 μm to form an ink receiving layer, thereby obtaining an inkjet recording sheet.

(Paint for ink receiving layer) Polyvinyl alcohol resin (trade name of Kuraray Co., Ltd .:
PVA-420): 80 parts Polyester resin (trade name of Plus Coat Chemical Co., Ltd .: Pluscoat Z-446): 20 parts Crosslinked polymethylmethacrylate fine particles (trade name of Sekisui Plastics Co., Ltd .: Tech Polymer MB20X-5):
0.5 part Water: 60 parts Methanol: 40 parts

Embodiment 2 FIG. An ink jet recording sheet was prepared in the same manner as in Example 1 except that a polyvinyl acetal resin (trade name of Sekisui Chemical Co., Ltd .: S-REC KX-1) was used in place of the polyvinyl alcohol resin used in Example 1. Obtained.

Embodiment 3 FIG. An inkjet recording sheet was obtained in exactly the same manner as in Example 1 except that an acrylic resin (trade name: Primal HA-8 manufactured by Nippon Acrylic Co., Ltd.) was used instead of the polyester resin used in Example 1. .

Embodiment 4 FIG. An inkjet recording sheet was obtained in the same manner as in Example 1 except that a polyvinyl acetal resin was used instead of the polyvinyl alcohol resin used in Example 3.

Embodiment 5 FIG. An ink jet recording sheet was obtained in the same manner as in Example 1 except that the following ink receiving layer coating material was used. (Ink receiving layer coating material) Polyvinyl acetal resin (Sekisui Chemical Co., Ltd. product name: S-REC KX-1): 50 parts Polyvinyl alcohol resin (Kuraray product name:
PVA-420): 45 parts Polyester resin (trade name of Plus Chemical Co., Ltd .: Pluscoat Z-446): 5 parts Crosslinked polymethylmethacrylate fine particles (trade name of Sekisui Plastics Co., Ltd .: Techpolymer MB20X-5):
0.5 part Water: 60 parts Methanol: 40 parts

Embodiment 6 FIG. An inkjet recording sheet was obtained in exactly the same manner as in Example 1 except that the mixing ratio of the polyvinyl acetal resin, polyvinyl alcohol resin, and polyester resin used in Example 5 was 25/25/50.

Embodiment 7 FIG. An inkjet recording sheet was obtained in exactly the same manner as in Example 1 except that an acrylic resin (trade name: Primal HA-8 manufactured by Nippon Acrylic Co., Ltd.) was used instead of the polyester resin used in Example 5. .

Embodiment 8 FIG. An inkjet recording sheet was obtained in exactly the same manner as in Example 1 except that an acrylic resin (trade name: Primal HA-8 manufactured by Nippon Acrylic Co., Ltd.) was used instead of the polyester resin used in Example 6. .

Comparative Example 1 The mixing ratio of the polyvinyl alcohol resin and the polyester resin used in Example 1 was 45 /
An ink jet recording sheet was obtained in the same manner as in Example 1 except that the number was changed to 55.

Comparative Example 2 An inkjet recording sheet was obtained in exactly the same manner as in Example 1 except that the polyester resin used in Example 1 (trade name: Pluscoat Z-446 manufactured by Kyosho Chemical Industry Co., Ltd.) was omitted.

Comparative Example 3. The mixing ratio of the polyvinyl acetal resin and the polyester resin used in Example 2 was 45 /
An ink jet recording sheet was obtained in the same manner as in Example 1 except that the number was changed to 55.

Comparative Example 4. An inkjet recording sheet was obtained in exactly the same manner as in Example 1 except that the polyester resin used in Example 2 (trade name: Pluscoat Z-446 manufactured by Kyosho Chemical Industry Co., Ltd.) was not used.

Comparative Example 5. The mixing ratio of the polyvinyl alcohol resin used in Example 3 and the acrylic resin (trade name: Primal HA-8 manufactured by Nippon Acrylic Co., Ltd.) was 45/5.
An inkjet recording sheet was obtained in the same manner as in Example 1 except that the number was changed to 5.

Comparative Example 6. Inkjet in the same manner as in Example 1 except that the mixing ratio of the polyvinyl acetal resin used in Example 4 and the polyacrylic resin (trade name: Primal HA-8 manufactured by Nippon Acrylic Co., Ltd.) was 45/55. A recording sheet was obtained.

Comparative Example 7 An inkjet recording sheet was obtained in exactly the same manner as in Example 1, except that the mixing ratio of the polyvinyl acetal resin, polyvinyl alcohol resin, and polyester resin used in Example 5 was 20/20/60.

Comparative Example 8 An inkjet recording sheet was obtained in exactly the same manner as in Example 1 except that the mixing ratio of the polyvinyl acetal resin, polyvinyl alcohol resin, and acrylic resin used in Example 7 was 20/20/60.

Comparative Example 9. Without using the polyester resin used in Example 5 (trade name: Plus Coat Z-446 manufactured by Kyosho Chemical Industry Co., Ltd.), except that the mixing ratio of the polyvinyl acetal resin and the polyvinyl alcohol resin was 50/50. An inkjet recording sheet was obtained in the same manner as in Example 1.

For the various ink jet recording sheets obtained above, a commercially available ink jet printer BJC is used.
Using -600J (manufactured by Canon Inc.), a recorded image was obtained by a test pattern having mixed color portions (red, green, blue).

(Evaluation) An evaluation method of each characteristic of the above recording sheet will be described below. In addition, the performance evaluation results thereof are shown in Tables 1 and 2. (1) Beading ... Dark and light unevenness was evaluated in the solid print portion of each mixed color. The case where no unevenness in light and shade was observed was evaluated as ◯, the case where it was confirmed was evaluated as x, and the condition between ◯ and × was evaluated as Δ.

(2) Border bleeding: ○ in the solid print portion of each mixed color where the boundary line can be clearly confirmed, and x when the color mixing occurs and the boundary line cannot be confirmed,
The middle of ○ and × was set as Δ.

(3) Ink Dryability ... In the solid print portion of each mixed color, the presence or absence of the transfer of the ink to the high-quality paper with the passage of time of the recorded image was evaluated. The case where transfer to the paper is stopped in less than 2 minutes is marked as ⊚, 2 minutes or more and less than 5 minutes is marked as ○, 5 minutes or more and less than 10 minutes is marked as Δ, and the case where it is transferred to the paper even after 10 minutes is marked as x. In this case, under each aging condition, a high-quality paper was superposed on the recorded image and reciprocated once with a 5 kg rubber roller, and then the high-quality paper was peeled off and the presence or absence of ink transfer was observed.

(4) Water resistance: The ink receiving layer was rubbed with a cotton swab soaked in water, and the number of times until the ink receiving layer was peeled off was measured. 50 times or more ◎, 20 to 49 times ○, 10
19 times were marked with Δ, and 9 times or less were marked with x.

[0046]

[Table 1]

[0047]

[Table 2]

As is clear from Table 2, in any of the examples, ink jet recording suitability such as beading, boundary bleeding, ink drying property and water resistance is excellent.
On the other hand, in the cases of Comparative Examples 1 to 9, all were inkjet recording sheets that could not achieve the target in a plurality of performance items.

Front Page Continuation (72) Inventor Masahide Takano 1551 Todaira, Higashimatsuyama City, Saitama Prefecture Nippon Paper Industries Co., Ltd. Imaging Technology Center

Claims (4)

[Claims] 1. An ink jet recording sheet comprising a substrate and at least one or more ink receiving layers provided thereon, wherein the ink receiving layer comprises (A) a polyvinyl acetal resin and / or a polyvinyl alcohol resin. (B)
Consists of at least one resin selected from the group of resins consisting of acrylic, polyester, styrene / acrylic, ethylene / vinyl acetate, vinyl acetate / acrylic, ethylene / vinyl acetate / acrylic, ethylene / acrylic, and polyethylene An inkjet recording sheet characterized by the above. 2. The ink jet recording sheet according to claim 1, wherein the mixing ratio of the component (A) and the component (B) in the ink receiving layer is 97/3 to 50/50. 3. The ink jet recording sheet according to claim 1, wherein the component (A) is a polyvinyl acetal resin. 4. The ink jet recording sheet according to claim 1, wherein the base material is a transparent plastic film.