JP3112642B2 - Inkjet recording sheet - 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 sheet for recording using an aqueous ink, and more particularly to an overhead projector (hereinafter abbreviated as OHP) film, a film for an illuminated panel, a sticker, a label, a drawing film,
The present invention relates to a recording medium suitable for full-color ink jet recording, which can be used for a high gloss film or the like.

[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 medium. Compared to the mainstream dot impact printers,
That high-speed recording is possible, that there is little noise during recording, that the device is relatively simple and that cost reduction is easy,
It is rapidly becoming popular because it is easy to make full color. Further, in addition to printers, applications to plotters, facsimile machines, copiers, and the like have been actively performed.

Conventionally, a recording medium on which an image is formed by using an ink jet recording method is disclosed in Japanese Patent Publication No. 3-26665.
Japanese Patent Publication No. 3-25352 discloses a recording paper provided with a coating layer comprising a mixed system of finely divided silica and a water-soluble polyvinyl alcohol resin on a base paper as described in Japanese Patent Application Publication No. Saponification degree of cast coated paper
Glossy paper on which a coating film comprising 90 mol% of a polyvinyl alcohol resin and a crosslinking agent is formed, 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 JP-A-0750.

[0004]

In recent years, as the performance of an ink jet recording apparatus has been improved, for example, by increasing the speed of recording and increasing the number of colors, the ink jet recording sheet has been required to be improved in the following broad points. Characteristics are required. (1) High ink absorption capacity and excellent ink drying property. (2) Good full-color recording characteristics such as inks not mixing when inks overlap. (3) The optical density of dots is high, and there is no blurring or unevenness of ink. (4) The dot shape is close to a perfect circle, the periphery is smooth,
High resolution. (5) Excellent water resistance. (6) A recorded image having excellent translucency can be obtained.

[0005] In particular, regarding the recording method of a translucent image,
As the speed of recording, the density of images, and the colorization progress, the deterioration of image quality due to poor ink fixing of a recording sheet has become a serious problem. That is, since the recording sheet having translucency 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 a recording surface provided on the surface of the base material. Since the ink is absorbed only by the layer, the drying ability of the ink is reduced. Therefore, especially in the case of color printing, color stain (bleeding of the boundary) due to color mixture is present at the boundary between different colors or at the boundary where a large amount of ink is attached such that two monochromatic inks are mixed. There was a drawback that it easily occurred.

Further, even if the drying property of the ink is good,
Because the fine ink droplets ejected from the printer are absorbed as they are without spreading on the ink receiving layer, the ink droplets become irregular and connected on the surface of the ink receiving layer, and when viewed macroscopically A beading phenomenon occurs in which the recorded image appears as shading unevenness. This phenomenon reduces the sharpness of the image together with the above-mentioned color stain. Therefore, a translucent recording sheet excellent in performances such as ink drying property, beading, and boundary bleeding, which are important issues in ink jet recording, has not yet been obtained.

The inventors of the present invention have conducted intensive studies on a light-transmitting recording sheet suitable for ink-jet recording, and have found that extremely good results can be obtained by using a specific resin for the recording layer. Reached the present invention. Accordingly, an object of the present invention is to provide a light-transmitting 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 light-transmitting substrate, wherein the ink-receiving layer comprises: (A) a polyvinyl acetal resin and / or a polyvinyl alcohol resin; ) Polyes
Ter resin, or polyester resin and acrylic, styrene / acryl, ethylene / vinyl acetate, vinyl acetate /
Acrylic, ethylene / vinyl acetate / acrylic, ethylene / acrylic, and with consisting of at least one resin selected from a resin group consisting of polyethylene, the
The mixing ratio of the component (A) and the component (B) is 97/3 to 50 /
50, which is achieved by 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 substrate include synthetic resin films such as polyester, polypropylene, polycarbonate, cellulose triacetate, and polyimide. Among the above base materials, a biaxially stretched polyester film is particularly preferable from the viewpoints of strength, heat resistance, dimensional stability, and cost. The light-transmissive substrate may have an arbitrary thickness of 6 to 300 μm. It is also possible to provide an adhesive layer between the ink receiving layer and the substrate.

[0010] The higher the degree of polymerization, the better the water resistance of the polyvinyl alcohol resin used in the present invention.
The polymerization degree is preferably from 500 to 3,500. Further, since the higher the degree of saponification, the better the ink absorbability, the degree of saponification is preferably from 70 to 90 mol%, and from the viewpoint of easy availability, it is particularly preferably from 75 to 85 mol%.

The polyvinyl acetal resin can be 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 polymerization degree of the polyvinyl alcohol resin as a raw material is preferably 500 to 3,500, and the saponification degree is preferably 70 to 90 mol%, particularly preferably 75 to 85 mol%. .

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

As the resin of the component (B) used in the present invention,
Is with polyester resin or with polyester resin
Acrylic resins optionally, styrene / acrylic copolymer resin, an ethylene / vinyl acetate copolymer resin, vinyl acetate /
At least one water-soluble and / or water-based fine particle dispersion selected from the group consisting of acrylic copolymer resins, ethylene / vinyl acetate / acrylic terpolymer resins, ethylene / acrylic copolymer resins, and polyethylene use the system resin
Mixed resin can be used .

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, the recording layer comprising only the resin (A) or the resin (B) is provided. Compared to the case, there is no boundary bleeding, the ink drying property is good, the ink has a uniform ink absorption property, and beading hardly occurs, so that a high-quality image can be obtained. The mixing ratio of (A) resin and (B) resin is
(A) 97 to 50 parts by weight of resin, (B) 3 to 3 parts by weight of resin
Preferably it is 50 parts by weight. As long as the ratio is within the range, the coating liquid having the same composition may be applied two or more times to form a multilayer, or a coating liquid having a different composition may be applied repeatedly to form a multilayer.

If the mixing ratio of the resin (B) in the ink receiving layer is less than 3% by weight in the resin, the ejected ink is difficult to spread, so that beading easily occurs and the sharpness of the image is reduced. On the other hand, when the content exceeds 50% by weight, the ink absorption capacity and the drying property are reduced, and border bleeding is likely to occur. (B) In selecting the resin,
It is necessary to select the recording sheet in consideration of the winding suitability (blocking) during winding.

The ink-receiving layer of the present invention may contain an inorganic or organic pigment, if necessary. 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, and the like. .

Examples of the organic pigment include fine particles such as polymethyl methacrylate resin, polystyrene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polycarbonate resin, acrylic resin and polyester resin. In the ink receiving layer of the present invention, it is also possible to further add a water-proofing agent, an antistatic agent, an ultraviolet absorber, a dye / pigment for coloring, and the like, and these various additives may be used alone. Or a mixture of them.

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 is 0.1
If it is less than μm, the ink absorbency is reduced, so that it is not possible to obtain a recording excellent in image quality. In addition, since the ink absorption ability increases with an increase in the coating thickness, the coating thickness may be determined according to the ink discharge amount of the printer.

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

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The ink jet recording sheet of the present invention is formed, for example, on a biaxially stretched polyester film by adding 80 parts by weight of polyvinyl alcohol having a polymerization degree of 2,000 and a saponification degree of 80 mol% and an acetalization degree of 20 mol. % Of a polyvinyl acetal having a degree of polymerization of 2000% by applying an aqueous solution 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 or 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 ink jet printer can be expanded more than before.

[0022]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, the addition amount of chemicals in Examples and Comparative Examples is parts by weight or% by weight unless otherwise specified.

Embodiment 1 FIG. As the translucent substrate, a 100 μm-thick polyester film (produced by Toyobo Co., Ltd .: Cosmoshine A-1,
100), a paint having the following composition was applied so that the thickness after drying was 5 μm to form an ink receiving layer, and an ink jet recording sheet was obtained.

(Coating for ink receiving layer) Polyvinyl alcohol resin (trade name of Kuraray Co., Ltd.)
PVA-420): 80 parts Polyester resin (trade name: Pluscoat Z-446, manufactured by Ryogo Chemical Industry Co., Ltd.): 20 parts Crosslinked polymethyl methacrylate fine particles (trade name, manufactured by Sekisui Plastics Co., Ltd .: Tech) Polymer MB20X-5):
0.5 parts Water: 60 parts Methanol: 40 parts

Embodiment 2 FIG. A sheet for ink jet recording was prepared in the same manner as in Example 1 except that a polyvinyl acetal resin (trade name: SREC KX-1 manufactured by Sekisui Chemical Co., Ltd.) was used instead of the polyvinyl alcohol resin used in Example 1. Obtained.

[0026]

[0027]

Embodiment 3 FIG. An ink jet recording sheet was obtained in exactly the same manner as in Example 1 using the following ink receiving layer paint. (Ink receiving layer paint) Polyvinyl acetal resin (trade name of Sekisui Chemical Co., Ltd .: Esrec KX-1): 50 parts Polyvinyl alcohol resin (trade name of Kuraray Co., Ltd.):
PVA-420): 45 parts Polyester resin (trade name: Pluscoat Z-446, manufactured by Syo Chemical Co., Ltd.): 5 parts Cross-linked polymethyl methacrylate fine particles (trade name, manufactured by Sekisui Plastics Co., Ltd .: Techpolymer) MB20X-5):
0.5 parts Water: 60 parts Methanol: 40 parts

Embodiment 4 FIG. An ink jet recording sheet was obtained in exactly the same manner as in Example 1, except that the mixing ratio of the polyvinyl acetal resin, the polyvinyl alcohol resin, and the polyester resin used in Example 3 was 25/25/50.

[0030]

[0031]

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 exactly the same manner as in Example 1 except that the sheet was set to 55.

Comparative Example 2 An ink jet 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 Ryogo Chemical Industry Co., Ltd.) was deleted.

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 exactly the same manner as in Example 1 except that the sheet was set to 55.

Comparative Example 4 An ink jet 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 Ryo Chemical Industry Co., Ltd.) was not used.

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

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

Comparative Example 7 An ink jet 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 changed to 20/20/60.

Comparative Example 8 An ink jet 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 changed to 20/20/60.

Comparative Example 9 Except that the mixing ratio between the polyvinyl acetal resin and the polyvinyl alcohol resin was set to 50/50 without using the polyester resin (trade name: Pluscoat Z-446 manufactured by Ryo Kagaku Kogyo Co., Ltd.) used in Example 5. In the same manner as in Example 1, an ink jet recording sheet was obtained.

A variety of ink jet recording sheets obtained above were used with a commercially available ink jet printer BJC.
Using -600J (manufactured by Canon Inc.), a recorded image was obtained by a test pattern having a mixed color portion (red, green, blue).

(Evaluation) A method for evaluating each characteristic of the above recording sheet will be described below. Tables 1 and 2 show the performance evaluation results. (1) Beading: In each solid printing portion of each mixed color, the shading unevenness was evaluated.も の indicates that no shading was observed, X indicates that it could be confirmed, and △ indicates the middle of と and ×.

(2) Boundary bleeding: In the solid printing portion of each mixed color, a mark in which a clear boundary line can be confirmed is indicated by "O"; a mark in which color mixing occurs and the boundary line cannot be confirmed is indicated by "X".
The middle point between ○ and × was indicated by Δ.

(3) Drying property of ink: The presence or absence of transfer of the ink to the high-quality paper due to the aging of the recorded image was evaluated in the solid printing portion of each mixed color.場合: no transfer to paper in less than 2 minutes, ○: 2 minutes to less than 5 minutes, Δ: 5 minutes to less than 10 minutes, ×: transfer to paper even after 10 minutes. In this case, high quality paper was superimposed on the recorded image under each aging condition, and after reciprocating once with a 5 kg rubber roller, 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 was measured. 50 times or more ◎, 20 to 49 times ○, 10
19 times were evaluated as Δ, and 9 times or less as ×.

[0046]

[Table 1]

[0047]

[Table 2]

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

Continuation of front page (72) Inventor Masahide Takano 1551 Higashihira, Higashimatsuyama-shi, Saitama Nippon Paper Industries Co., Ltd. Image Engineering Center (56) References JP-A-2-38088 (JP, A) JP-A-2-301480 (JP) JP-A-4-214382 (JP, A) JP-A-4-78570 (JP, A) JP-A-8-174994 (JP, A) JP-A-8-169176 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/00 B32B 27/30

Claims (3)

(57) [Claims] An ink jet recording sheet comprising at least one ink-receiving layer provided on a light-transmitting substrate, wherein the ink-receiving layer comprises (A) a polyvinyl acetal resin and / or a polyvinyl alcohol. Resin and
(B) polyester resin or a group of resins consisting of polyester resin and acrylic, styrene / acrylic, ethylene / vinyl acetate, vinyl acetate / acrylic, ethylene / vinyl acetate / acrylic, ethylene / acrylic, and polyethylene And at least one resin selected from the group consisting of (A) and (B).
97/3 to 50/50 . 2. Component (A) is a polyvinyl acetal resin.
The inkjet recording system according to claim 1, wherein
To 3. The substrate is a transparent plastic film.
For inkjet recording according to claim 1 or 2
Sheet.