JPH08207426A - Ink jet recording sheet - Google Patents

Abstract

PURPOSE: To obtain an ink jet recording sheet having superior ink-accepting properties and an excellent bonding workability without a need for a post- treatment, such as bonding and waterproofing, using an auxiliary material after the output of an image. CONSTITUTION: An ink jet recording sheet provided with an ink-accepting layer 2 formed by loading a hydrophilic resin, as required, in a thermoplastic resin, a crystalline plasticizer, and a tackifier on one surface of a substrate 1 contains 30-300 pts.wt, crystalline plasticizer, 10-150 pts.wt. tackifier, and 1-100 pts.wt. hydrophilic resin per 100 pts.wt. of thermoplastic resin.

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 sheet, and more particularly to an ink jet recording sheet which can be laminated only by heating after outputting an image.

[0002]

2. Description of the Related Art Ink jet printers are used to eject minute droplets of ink by various operating principles and attach them to a recording sheet such as paper to record images and characters, but the output method is simple. It is characterized by low noise, low cost, and the like, and has rapidly spread in recent years in various applications as a recording device for various figures including Kanji and color images.

By the way, when the recording sheet after output is used for a display, it is generally fixed to a wall surface or the like with an adhesive or a thumbtack. Also, when displaying in places exposed to rainwater or direct sunlight, such as an outdoor display, a transparent film is usually laminated to protect the image surface, and the back surface is covered with an adhesive tape, thumbtack, or other auxiliary material. There is a method of fixing, or a method of outputting a mirror image on the image receiving surface of the back print sheet, waterproofing the image receiving surface, and adhering it to the wall surface with an adhesive. However, these require post-processing after image output, which is troublesome and costly and inconvenient. Furthermore, waterproofing is a work of applying a liquid to a large area, and at the same time a uniform coating film cannot be obtained, there is also a health problem such as the worker inhaling the solvent in which the coating liquid has volatilized. Was desired.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide an ink jet recording sheet which can be attached only by heating after outputting an image. To do.

[0005]

Means for Solving the Problems The inventors of the present invention have made extensive studies to solve the drawbacks of the conventional ink jet recording sheet. As a result, they have found that by using a thermoplastic resin, a crystalline plasticizer and a tackifier in the ink receiving layer, the ink receiving property is excellent and heat adhesion is possible, and the problems of the prior art are solved. The present invention has been completed based on such findings.

That is, the ink jet recording sheet of the present invention is characterized in that an ink receiving layer containing a thermoplastic resin, a crystalline plasticizer and a tackifier is provided on one surface of a substrate. .

The present invention will be described below with reference to the drawings. Here, FIG. 1 is a cross-sectional view of an inkjet recording sheet according to the present invention.

The substrate 1 used in the present invention is a plastic film such as polyester, polycarbonate, polypropylene, polyvinyl chloride or acetyl cellulose,
Examples include paper and cloth. The plastic film may be kneaded with an ultraviolet absorber in order to improve the weather resistance of the printed image, and the paper or cloth is preferably water-resistant. Further, these base materials may be appropriately selected such that they are white when viewed from the ink receiving layer side and transparent when viewed from the base material side.

The ink receiving layer 2 is basically a layer composed of a thermoplastic resin, a crystalline plasticizer and a tackifier.

The thermoplastic resin is the source of the adhesive force and the adhesive force. Specific examples include vinyl acetate, acrylic resin, styrene resin, polyamide, alkyd resin, cyanoacrylate, polyester, phenoxy, polysulfone, polyallylsulfone, polyethylene, (meth) acrylic acid ester, styrene- (meth) acrylic acid ester, Styrene-butadiene, styrene-isoprene block polymer, ethylene-vinyl acetate, vinyl acetate- (meth) acrylic acid ester, ethylene-vinyl chloride, ethylene- (meth) acrylic acid ester, ethylene- (meth) acrylic acid, vinyl chloride- Examples thereof include vinylidene chloride, polybutadiene, urethane, vinylpyrrolidone-styrene, vinylpyrrolidone- (meth) acrylic acid ester and the like, and one kind or a mixture of two or more kinds thereof is used. Further, among the thermoplastic resins, hydrophilic resins and the like are particularly preferable in terms of ink receptivity. In particular,
Examples thereof include sulfo group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, polyethylene oxide crosslinked product, ethylene vinyl alcohol, and water-soluble polyester. This kind of product is Gocelan L-03
01, L-0302, Gohsefimer LL-02, Soarnol, Polyester WR-900, WR-901,
XWR-930, XWR-950 (above, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Aqua Coke (manufactured by Sumitomo Seika Kogyo Co., Ltd.), and the like are commercially available, but all of them are preferably used in the present invention. it can.

Since the crystalline plasticizer is solid at room temperature, it does not give plasticity to the resin and melts by heating to swell or soften the resin. At room temperature, the non-adhesive ink receiving layer is heated. It acts to develop tackiness. As a result, the ink-receiving layer does not lose its tackiness because the supercooled state continues for a considerably long time. Normal,
Unlike ordinary heat-sensitive adhesives, the adhesive strength is retained for several days, which is advantageous in that the laminating work can be easily performed without using a machine such as a heat laminator.

The crystalline plasticizer used in the present invention includes
The melting point is preferably about 50 to 100 ° C. This is because if the melting point is too close to room temperature, blocking easily occurs, and if it is too high, heating work becomes inconvenient. The main crystalline plasticizers are diphenyl phthalate, dicyclohexyl phthalate, dihexyl phthalate, dihydroabietyl phthalate, dimethyl isophthalate, sucrose benzoate, ethylene glycol dibenzoate, trimethylolethane tribenzoate, tribenzoic acid. Acid glyceride, pentaerythritol tetrabenzoate, sucrose octaacetate, tricyclohexyl citrate, N-cyclohexyl-p-toluenesulfonamide and the like. Further, the addition amount of the crystalline plasticizer is 30 to 30 with respect to 100 parts by weight of the thermoplastic resin.
0 parts by weight is preferable, and 50 to 150 parts by weight is more preferable. This is because when the amount is 30 to 300 parts by weight, the effect of developing tackiness is very large.

Tackifiers are used to improve initial or residual tack. The type and amount of tackifier is limited by the compatibility with the raw material polymer,
Affects viscosity curve and storability. Therefore, depending on the type of thermoplastic resin used, it cannot be said unconditionally, rosin-based resin and its derivatives, butyral resin, polyisobutylene, acrylonitrile polymer, aliphatic petroleum resin, aromatic petroleum resin, terpene resin, phenol resin, Terpene-indene resin, xylene resin and the like can be used. The addition amount of the tackifier is preferably 10 to 150 parts by weight with respect to 100 parts by weight of the thermoplastic resin. 1
The amount of 0 parts by weight or more is for obtaining sufficient initial tackiness, and the amount of 150 parts by weight or less is for improving the ink receptivity.

The above-mentioned thermoplastic resin, crystalline plasticizer and tackifier can be used alone or as a mixture of two or more kinds as an aqueous emulsion or an organic solvent solution.

The coating solution may be prepared by dispersing a crystalline plasticizer in water and mixing it with an emulsion, or by melting the crystalline plasticizer and emulsifying it in water and then mixing it with the emulsion. The method includes, but is not limited to, a method of dispersing the emulsion in the melted crystalline plasticizer.

Further, a hydrophilic resin may be added to the ink receiving layer in order to improve the ink receiving property. As the hydrophilic resin, albumin, gelatin, casein, starch, gum arabic, natural resin such as sodium alginate, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinylpyrrolidone, polyamide, polyacrylamide, polyhydroxyethyl methacrylate, polyphenylacetoacetal, polyethyleneimine Examples thereof include synthetic resins such as polyvinyl alcohol, polyester, sodium polyacrylate, and acrylic acid ester copolymer. The amount of hydrophilic resin added is
It is preferably 1 to 100 parts by weight with respect to 100 parts by weight of the thermoplastic resin. The amount of 1 part by weight or more is for improving the ink receiving property, and the amount of 100 parts by weight or less is for further improving the tackiness. In addition, it is possible to use other resins in combination because of the close contact with the support and the balance with the thermoplastic resin.

Further, in order to further improve the ink absorbability and the blocking prevention property, silica, clay, talc, diatomaceous earth, calcium carbonate, barium sulfate, aluminum silicate, synthetic zeolite, to the extent that the above-mentioned action is not impaired. Fillers such as smectite, alumina, zinc oxide and titanium oxide may be mixed and dispersed in the ink receiving layer.

If necessary, various additives such as a dispersant, a fluorescent dye, a pH adjusting agent, an antifoaming agent, a wetting agent, a preservative, an antioxidant and a surfactant are added to the same layer in the coating film. It can be added within a range that does not impair the performance.

The thickness of the ink receiving layer is 3 to 100 μm.
m is preferable, and 5 to 50 μm is more preferable. The reason why the thickness is 3 μm or more is to obtain good ink absorbency.
The reason why the thickness is set to 00 μm or less is in consideration of productivity.
When the present recording sheet is used for so-called back printing in which the recording sheet is printed on the ink receiving layer and viewed from the surface of the substrate, the thickness of the layer is particularly preferably 5 to 30 μm. This is because the ink satisfactorily penetrates to the interface between the ink receiving layer and the substrate, and a clear image is obtained from the substrate surface.

The ink jet recording sheet of the present invention comprises
Although the above-mentioned configuration is mainly used, it is also possible to appropriately perform a heat treatment and then laminate a release sheet, or a laminate of release sheets and then a heat treatment. If necessary, an undercoat layer may be provided under the ink receiving layer,
Further, an ultraviolet absorber may be mixed with the undercoat layer in consideration of weather resistance and the like. This ultraviolet absorber can be laminated on the surface opposite to the ink receiving layer.

The ink jet recording sheet of the present invention comprises
It can be produced by coating and drying the coating solution having the above composition on a substrate by a roll coater, a wire bar coater, an air knife coater, a gravure coater method or the like.

[0022]

As described above, by providing an ink receiving layer formed by adding a thermoplastic resin, a crystalline plasticizer, a tackifier and, if necessary, a hydrophilic resin on the substrate, the ink receiving property is improved. Excellent workability that does not require post-processing such as sticking treatment using auxiliary materials or waterproof treatment after image output, and can obtain long-term stickiness (open time) just by heating. It is possible to obtain an excellent inkjet recording sheet.

[0023]

Embodiments of the present invention will be described below. In addition, "part" in this example represents the weight basis of solid content unless otherwise specified.

Example 1 A transparent polyester film having a thickness of 75 μm (Lumirror Q
(-81: manufactured by Toray Industries, Inc.), the following substances were dissolved or dispersed in water to apply a coating liquid for the ink receiving layer, and the mixture was dried with a drier 6
After drying at 0 ° C. for 5 minutes, an inkjet recording sheet having an ink receiving layer having a dry film thickness of 10 μm was obtained.

[Ink Receiving Layer] Thermoplastic resin (ethylene-vinyl acetate copolymer) 100 parts (Movinyl 730: Hoechst Synthetic Co., Ltd.) Crystalline plasticizer 150 parts (dicyclohexyl phthalate) Tackifier (rosin ester) 100 copies (SE-E-730-55: Arakawa Chemical Industry Co., Ltd.)

Example 2 75 μm thick transparent polyester film (Lumirror Q
(-81: manufactured by Toray Industries, Inc.), the following substances were dissolved or dispersed in water to apply a coating liquid for the ink receiving layer, and the mixture was dried with a drier 6
After drying at 0 ° C. for 5 minutes, an inkjet recording sheet having an ink receiving layer having a dry film thickness of 10 μm was obtained.

[Ink Receiving Layer] Thermoplastic resin (ethylene-vinyl acetate copolymer) 100 parts (Movinyl 730: Hoechst Synthetic Co., Ltd.) Crystalline plasticizer 150 parts (dicyclohexyl phthalate) Tackifier (rosin ester) 100 parts (SE-E-730-55: Arakawa Chemical Industry Co., Ltd.) Hydrophilic resin (polyvinyl alcohol) 10 parts (Gosenol KH-17: Nippon Synthetic Chemical Industry Co., Ltd.)

Example 3 75 μm thick transparent polyester film (Lumirror Q
(-81: manufactured by Toray Industries, Inc.), the following substances were dissolved or dispersed in water to apply a coating liquid for the ink receiving layer, and the mixture was dried with a drier 6
After drying at 0 ° C. for 5 minutes, an inkjet recording sheet having an ink receiving layer having a dry film thickness of 10 μm was obtained.

[Ink receiving layer] 100 parts of thermoplastic resin (acrylic resin) (Sumikaflex 753: manufactured by Sumitomo Chemical Co., Ltd.) Crystalline plasticizer 150 parts (dicyclohexyl phthalate) Tackifier (rosin ester) 100 parts ( SE-E-730-55: Arakawa Chemical Industry Co., Ltd.) Hydrophilic resin (polyvinyl alcohol) 10 parts (Gosenol KH-17: Nippon Synthetic Chemical Industry Co., Ltd.)

Example 4 75 μm thick transparent polyester film (Lumirror Q
(-81: manufactured by Toray Industries, Inc.), the following substances were dissolved or dispersed in water to apply a coating liquid for the ink receiving layer, and the mixture was dried with a drier 6
After drying at 0 ° C. for 5 minutes, an inkjet recording sheet having an ink receiving layer having a dry film thickness of 10 μm was obtained.

[Ink Receiving Layer] Thermoplastic resin (ethylene-vinyl acetate copolymer) 100 parts (Movinyl 730: Hoechst Synthetic Co., Ltd.) Crystalline plasticizer 150 parts (dicyclohexyl phthalate) Tackifier (rosin ester) 100 parts (SE-E-730-55: Arakawa Chemical Industry Co., Ltd.) Hydrophilic resin (polyvinyl alcohol) 100 parts (Gosenol KH-17: Nippon Synthetic Chemical Industry Co., Ltd.)

Example 5 75 μm thick transparent polyester film (Lumirror Q
(-81: manufactured by Toray Industries, Inc.), the following substances were dissolved or dispersed in water to apply a coating liquid for the ink receiving layer, and the mixture was dried with a drier 6
After drying at 0 ° C. for 5 minutes, an inkjet recording sheet having an ink receiving layer having a dry film thickness of 10 μm was obtained.

[Ink Receiving Layer] Thermoplastic resin (ethylene-vinyl acetate copolymer) 100 parts (Movinyl 730: Hoechst Synthetic Co., Ltd.) Crystalline plasticizer 250 parts (dicyclohexyl phthalate) Tackifier (rosin ester) 100 parts (SE-E-730-55: Arakawa Chemical Industry Co., Ltd.) Hydrophilic resin (polyvinyl alcohol) 10 parts (Gosenol KH-17: Nippon Synthetic Chemical Industry Co., Ltd.)

Comparative Example 1 75 μm thick transparent polyester film (Lumirror Q
(-81: manufactured by Toray Industries, Inc.), the following substances were dissolved or dispersed in water to apply a coating liquid for the ink receiving layer, and the mixture was dried with a drier 6
After drying at 0 ° C. for 5 minutes, an inkjet recording sheet having an ink receiving layer having a dry film thickness of 10 μm was obtained.

[Ink Receiving Layer] Thermoplastic resin (ethylene-vinyl acetate copolymer) 100 parts (Movinyl 730: Hoechst Synthetic Co., Ltd.) Crystalline plasticizer 5 parts (dicyclohexyl phthalate) Tackifier (rosin ester) 100 copies (SE-E-730-55: Arakawa Chemical Industry Co., Ltd.)

Comparative Example 2 75 μm thick transparent polyester film (Lumirror Q
(-81: manufactured by Toray Industries, Inc.), the following substances were dissolved or dispersed in water to apply a coating liquid for the ink receiving layer, and the mixture was dried with a drier 6
After drying at 0 ° C. for 5 minutes, an inkjet recording sheet having an ink receiving layer having a dry film thickness of 10 μm was obtained.

[Ink Receiving Layer] Thermoplastic resin (ethylene-vinyl acetate copolymer) 100 parts (Movinyl 730: Hoechst Synthetic Co., Ltd.) Crystalline plasticizer 500 parts (dicyclohexyl phthalate) Tackifier (rosin ester) 100 copies (SE-E-730-55: Arakawa Chemical Industry Co., Ltd.)

Comparative Example 3 75 μm thick transparent polyester film (Lumirror Q
(-81: manufactured by Toray Industries, Inc.), the following substances were dissolved or dispersed in water to apply a coating liquid for the ink receiving layer, and the mixture was dried with a drier 6
After drying at 0 ° C. for 5 minutes, an inkjet recording sheet having an ink receiving layer having a dry film thickness of 10 μm was obtained.

[Ink Receiving Layer] Thermoplastic resin (ethylene-vinyl acetate copolymer) 100 parts (Movinyl 730: Hoechst Synthetic Co., Ltd.) Crystalline plasticizer 150 parts (dicyclohexyl phthalate) Tackifier (rosin ester) 100 parts (SE-E-730-55: Arakawa Chemical Industry Co., Ltd.) Hydrophilic resin (polyvinyl alcohol) 400 parts (Gosenol KH-17: Nippon Synthetic Chemical Industry Co., Ltd.)

Then, Examples 1 to 1 obtained as described above
Using the inkjet recording sheets of No. 5 and Comparative Examples 1 to 3, an output sample was prepared with an inkjet printer (BJC600J: manufactured by Canon Inc.). Then, the dryness and sharpness of the printed image were visually evaluated. Regarding the evaluation results, in terms of dryness, the one with a fast dryness was marked with ◯, the one with a slight slowness was marked with Δ, and the slower one was marked with x. Further, in terms of sharpness, ◎ means sharp printing, ○ means slightly bleeding, and X means considerably bleeding.

Further, with respect to tackiness, the open time and tackiness were evaluated by the following methods.

Open time: After the adhesiveness was developed by heating, it was allowed to stand at 20 ° C. and 65% RH and the duration of its adhesive strength was measured. Regarding the evaluation result, the adhesive strength duration is 1
The time is from 24 hours to Δ, and the time from 24 hours to 24 hours. In addition, when it did not develop or when the adhesive strength duration was less than 1 hour, it was marked with x.

Adhesive strength: After the adhesiveness is developed by heating, it is immediately attached to a plastic film, and JISZ-02 is used.
According to 37, the adhesive strength was measured by peeling 180 degrees.

The results are shown in Table 1.

[0045]

[Table 1]

As shown in Table 1, in Example 1,
Since the hydrophilic resin was not added, the ink receptivity was slightly inferior, but sufficient tackiness was obtained and it could be used. In Example 2, the addition of the hydrophilic resin improved the ink receptivity and the tackiness was sufficient. In Example 3, an acrylic thermoplastic resin was used and a hydrophilic resin was added to it, but the ink receptivity and tackiness were very good. Example 4
In Comparative Example 1, since the amount of the hydrophilic resin added to the thermoplastic resin was rather large, the tackiness was slightly inferior, but sufficient ink receptivity was obtained and it was usable. In Example 5, since the amount of the crystalline plasticizer added to the thermoplastic resin was rather large, the adhesiveness was slightly inferior, but sufficient ink acceptability was obtained.
It could be used.

On the other hand, in Comparative Example 1, since the amount of the crystalline plasticizer added to the thermoplastic resin was small, the adhesive strength was not exhibited even when heated. In Comparative Example 2, the amount of the crystalline plasticizer added to the thermoplastic resin was too large, and thus the developed adhesive force was weak. Moreover, the ink receptivity was not enough to withstand use. In Comparative Example 3, since the amount of the hydrophilic resin added to the thermoplastic resin was too large, the ink receptivity was good, but the adhesive strength was not exhibited.

[0048]

As described above, in the present invention, the ink receiving layer is formed by adding a thermoplastic resin, a crystalline plasticizer, a tackifier and, if necessary, a hydrophilic resin on a substrate, thereby providing an ink receiving layer. Since it does not require adhesive treatment using auxiliary materials after image output, and it is possible to obtain long-term adhesive persistence just by heating, it has excellent laminating workability. Since it is not exposed to the outside air, it is possible to obtain an ink jet recording sheet having good weather resistance without requiring waterproof treatment.

[Brief description of drawings]

FIG. 1 is a sectional view of an inkjet recording sheet according to an embodiment of the present invention.

[Explanation of symbols]

 1 ... Base material 2 ... Ink receiving layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Matsuyama 4-63 Suzuya, Yono City, Saitama Prefecture Kimoto Central Research Institute

Claims (4)

[Claims] 1. An inkjet recording sheet having an ink receiving layer provided on one surface of a substrate, wherein the ink receiving layer contains a thermoplastic resin, a crystalline plasticizer and a tackifier. Recording sheet. 2. The ink receiving layer, wherein the crystalline plasticizer is 30 to 300 parts by weight and the tackifier is 10 to 150 parts by weight with respect to 100 parts by weight of the thermoplastic resin. 1. The inkjet recording sheet according to 1. 3. The ink jet recording sheet according to claim 1, wherein the ink receiving layer contains a hydrophilic resin. 4. The ink jet recording sheet according to claim 3, wherein the ink receiving layer contains 1 to 100 parts by weight of a hydrophilic resin with respect to 100 parts by weight of a thermoplastic resin.