JPH09158087A - Recording paper having pseudoadhesivity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain recording paper having pseudo-adhesivity whose surface layer contains a fixing agent to fix dyestuffs in water-base ink thereto, and which has high-speed recordability allowing a large amount of printing at a time and excellent applicability to ink-jet recording to be useful for offset printing. SOLUTION: This recording paper comprises a surface layer which is provided on a surface of substrate paper and has pseudo-adhesivity owing to an adhesive contained in the layer, so that dyestuffs in water-base ink is fixed to the surface or inside of the pseudo-adhesive layer as recording layer which contains a fixing agent composed of a cationic water-soluble polymer and/or oligomer such as a quaternary ammonium salt derivative of polyethyleneimine, polyamine-polyamide epichlorohydrin, cationic polyvinyl alcohol or cationic starch, and has a liquid transfer quantity of 10-30ml/m<2> when the contact time is 75msec, rate of absorption of 1.4-3.0ml.ml<-2> .msec<-1/2> and wet time of <=100msec.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet having a pseudo-adhesive recording surface, and more particularly to a recording sheet having a pseudo-adhesive recording surface having excellent ink jet recording suitability.

[0002]

2. Description of the Related Art In recent years, after printing with an offset printer or an electrophotographic printer on the pseudo adhesive layer of a paper provided with a pseudo adhesive layer that can be temporarily adhered and peeled off when necessary, It has been practiced to post more information at low cost by making the pseudo adhesive layers face each other and press-bonding them to form one postcard.

This has been used as a postcard having confidentiality in accordance with the revision of the Postal Law. Two or three-fold recording sheets are superposed and pseudo-bonded in the shape of a postcard so that the inside is personalized. After concealing various information such as information, it is mailed, and the recipient peels off the pseudo adhesive portion and reads the hidden information. In this case, as a method of recording information on the pseudo-adhesive layer, printing of a ground pattern or standard information by an offset printing machine and / or printing of variable information by an electrophotographic printer is used exclusively. .

On the other hand, the ink jet recording method has recently been used.
Because of its low running cost and high-speed recording performance,
Not only is it attracting attention as a recording method that replaces conventional printing presses such as letterpress and offset, but by combining it with a computer, it is possible to respond instantly to a variety of variable information. It is beginning to be used as a recording method.

The recording paper used in this recording method has an excellent ink absorption rate, does not leave unfixed ink on the paper surface for a long time, has a large ink absorption capacity, and has a clear solid recording area boundary. Yes, it has excellent image fastness such as water resistance and light resistance, ink dots do not bleed too much, and it has uniform and sharp edges. No suitable pseudo-adhesive layer for recording paper is known for inkjet recording.

That is, when ink jet recording is performed on a pseudo adhesive layer of a conventional pseudo adhesive recording paper, since the ink absorbing speed and the absorbing capacity of the pseudo adhesive layer are small, bleeding occurs at the boundary of the recording portion or after printing. When the process is wound up or postcards are formed, unfixed ink rubs against other parts or is piled up, which causes stains on the non-printed surface, and information cannot be transmitted correctly. Further, even if the ink is sufficiently dried, there is a drawback in that recorded information may be lost due to lack of water resistance when wet with water.

[0007]

DISCLOSURE OF THE INVENTION As a result of intensive studies for solving the above-mentioned drawbacks, the present inventors have found that a fixing agent for fixing a dye in an aqueous ink on the surface and / or inside of the pseudo adhesive layer. It has been found that the inclusion of the compound significantly improves the printability for water-based ink and has reached the present invention. Therefore, an object of the present invention is to provide a pseudo-adhesive recording paper having a pseudo-adhesive layer having excellent ink jet recording characteristics.

[0008]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
A coated paper comprising a base paper and a pseudo-adhesive layer provided on the surface of the base paper, wherein the pseudo-adhesive layer fixes a dye in an aqueous ink on the surface and / or inside of the layer. It was achieved by a pseudo-adhesive recording paper which is characterized by a recording layer containing a fixing agent.

The base paper used in the present invention can be appropriately selected and used from the base papers conventionally used for providing the pseudo adhesive layer. The pseudo-adhesive layer in the present invention is mainly prepared, for example, by using an adhesive such as rewetting glue or natural rubber or synthetic rubber as a base material, and mixing an organic pigment and / or an inorganic pigment therein.

Specific examples of the above-mentioned adhesive include natural rubber latex obtained by graft-copolymerizing an acrylic monomer such as methyl methacrylate, acrylic rubber emulsion, SBR emulsion, ethylene-vinyl acetate emulsion, and microencapsulated adhesive. Agent and P
Examples thereof include water-soluble polymers such as VA, PEG, water-soluble cellulose derivatives, and soluble starches.

Specific examples of the above-mentioned pigments include synthetic silica, kaolin, clay, calcium carbonate, aluminum hydroxide, aluminum oxide, plastic pigments and starches. In the present invention, further, a dispersant, a defoaming agent, an antioxidant, a conductive agent,
You may add auxiliary agents, such as a mold release agent.

The surface and / or the inside of the pseudo adhesive layer in the present invention contains a fixing agent for the dye contained in the water-based ink from the viewpoint of improving the ink jet recording suitability such as imparting water resistance to the ink jet recording image. Let In recent years, a weak anionic dye such as a carboxyl group is often used as the dye of the water-based ink for inkjet recording. Therefore, in the present invention, as the fixing agent, a cationic water-soluble polymer and / or a cationic water-soluble polymer is used. It is preferable to include the water-soluble oligomer of.

Examples of the above-mentioned cationic water-soluble polymer or oligomer include polyethyleneimine quaternary ammonium salt derivatives, polyamine polyamide epichlorohydrin, cationic polyvinyl alcohol, cationic starch and low molecular weight products thereof. Can be mentioned. These fixing agents may be applied as an aqueous solution on the surface of the pseudo adhesive layer, or may be contained in the coating liquid for the pseudo adhesive layer.

In the present invention, the above fixing agents may be used alone or in combination. When the aqueous solution of the fixing agent is applied to the pseudo adhesive layer, it can be applied before or after the pseudo adhesive layer is dried.
The amount of the fixing agent used is preferably 0.15 g to 0.65 g / m ² . If it is less than 0.25 g / m ² , the dye fixing effect is not sufficient, and if it exceeds 0.7 g / m ² , the pseudo-adhesiveness becomes insufficient.

In the present invention, by adjusting various components of the pseudo adhesive layer, the characteristics of the surface such as liquid transfer amount, absorption time and wetting time in the dynamic absorption liquid test, for printing with the water-based ink are determined. Can be adjusted. In the present invention, the dynamic liquid absorption test is performed by the “Paper and board liquid absorption test method (J Tappi No. 51
-87) '', use a liquid with a specified interfacial tension,
This is done by examining the dynamic liquid absorption behavior.

The dynamic liquid absorption test clarifies the relationship between the contact time of liquid with paper and the transfer amount of liquid with paper.
The result is represented as a liquid absorption curve obtained by plotting the square root of the contact time on the horizontal axis and the liquid transfer amount on the vertical axis, as illustrated in FIG. Wetting time means the time during which the liquid transfer amount does not change until the liquid absorption curve shows a slope,
The absorption coefficient means the initial gradient of the liquid absorption curve after the wetting time. Wetting times may not be observed if the interfacial tension of the liquid used in the test is low.

In the present invention, in the dynamic liquid absorption test using a liquid having an interfacial tension of 35 dyne / cm under the experimental conditions of 20 ° C. and 65% RH, the liquid transfer at a contact time of 75 msec. The amount is 8.5 to 30 ml / m ² , and the absorption coefficient is 1.
It is preferable that the wetting time is 4 to 3.0 ml · m ⁻² · ms ^−1/2 and the wetting time is 400 msec or less.
It is preferably 0 to 30 ml / m ² . Contact time 75ms
If the liquid transfer amount in ec is less than 8.5 ml / m ² , the instantaneous ink transfer property to the paper will be poor, so image fixing will be slow, and if it exceeds 30 ml / m ² , the ink transfer / permeability will be too good. Therefore, the image is easily blurred.

Since the absorption coefficient means the initial transition rate of the liquid, if it is less than 1.4 ml · m ⁻² · ms ^−1/2 , the instantaneous fixability of ink droplets deteriorates and rubbing during high speed printing. Or contact with other parts may stain the printed surface.
On the other hand, if it is larger than 3.0 ml · m ⁻² · ms ^{−1 / 2} , the bleeding of ink droplets becomes large, so that good printing quality cannot be obtained. The wetting time means the time until the liquid starts to penetrate into the liquid receiving layer, so if it exceeds 400 msec,
As in the case where the absorption coefficient is small, it causes stains on the printed surface.

As the dye of the water-based ink used for ink jet recording, it is preferable to use a dye having a weak anionic group such as a carboxyl group in its molecule. The dye is physically adsorbed to the pigment mixed in the recording layer and the surface of the micropores generated during drying in the coating layer, and the ionic group of the dye binds to the fixing agent to become water-insoluble. Is established. The recording paper of the present invention is a special paper having a coating layer having a pseudo-adhesive property, but high-speed ink jet recording is possible, and at that time, ink drying property, print quality and image storability (fastness) are obtained. ) Is a highly functional recording paper.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The recording sheet of the present invention capable of pseudo-adhesion is prepared by adding an adhesive, a pigment and, if necessary, an auxiliary agent to prepare a pseudo-adhesive composition, and applying the composition to the surface of a base paper It can be easily obtained by applying and drying an aqueous solution of a fixing agent on a dried surface or an undried surface. The fixing agent may be added to the pseudo adhesive composition in advance. In this case, the application of the fixing agent aqueous solution after applying the pseudo adhesive composition may be omitted.

[0021]

In the recording paper of the present invention, the pseudo-adhesive layer has ink jet recording suitability, so that high speed recording can be performed at once by an ink jet printer regardless of whether it is standard information or variable information. This makes it particularly suitable for inexpensively mailing large amounts of information.

[0022]

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. The test methods and evaluation criteria used in Examples and Comparative Examples are as follows, and “%” represents “% by weight” unless otherwise specified.

(1) Evaluation of print quality by ink jet recording An ink jet printer (MJ700-V2C: manufactured by Seiko Epson Corporation) and an interfacial tension of about 50 dyne /
Printing was performed using cm black ink, and a sensory test was performed on the print quality according to the following criteria. (A) Bleeding-There is almost no crushing of characters due to bleeding- ○ -There is crushing of characters due to bleeding but it does not interfere with decoding ... △ -Something with crushing of characters due to bleeding ... ×

(B) Image storability (fastness) -No image distortion or bleeding when immersed in water- ○ -Image distortion or bleeding when immersed in water, but that does not interfere with decoding-・ △ ・ Image is distorted or bleeding when immersed in water. × (c) Image fixing speed ・ Fixed within 10 seconds after printing solid (4 mm x 100 mm) area ○ ○ ・ Solid (4 mm x 100 mm) area printing Those that do not settle within 10 seconds after ...

(2) Adhesive strength After the sample was placed in an environment of 20 ° C. and 65% RH for 24 hours or more, 60 kgf /
After pressure bonding with cm pressure, 2 hours later, JISK6854
The T-peel test was performed according to・ Adhesive strength is moderate and there are almost no defects on the surface after peeling ・ ・ ・ ○ ・ Adhesive strength is improper ・ ・ ・ ・ ・ ・ ×

Embodiment 1 FIG. Methyl methacrylate graft copolymerized natural rubber latex as an adhesive 100 parts (solid content: GS5-50.55 manufactured by KU Kasei Co., Ltd.)
%), 75 parts of synthetic silica having a weight average particle diameter of 2.5 μm,
And 85 parts of acetylated starch were mixed to obtain a pseudo adhesive composition. Next, this adhesive composition was added at 104.5 g /
acidic woodfree paper surface of m ^2, the amount of coating. The coating is 5 g / m ² (solid basis), Further, polyamine polyamide epichlorohydrin (Showa Kobunshi, Ltd. PF-600)
Was applied so that the polyamine epichlorohydrin content would be 0.3 g / m ² to obtain a recording paper. The results of measuring and evaluating the dynamic liquid absorbency, adhesive strength, and print quality using this recording paper are as shown in Table 1.

[0027]

[Table 1]

Embodiment 2 FIG. 80 basis weight instead of acidic high-quality paper
A recording paper was obtained in exactly the same manner as in Example 1 except that a neutral high-quality paper of g / m ² was used. The results of measuring and evaluating the dynamic liquid absorbency, adhesive strength, and print quality using this recording paper are shown in Table 1.

Embodiment 3 FIG. 50 parts of synthetic silica used,
A recording sheet was obtained in exactly the same manner as in Example 1 except that the amount of acetylated starch was changed to 135 parts. The results of measuring and evaluating the dynamic liquid absorbency, adhesive strength, and print quality using this recording paper are as shown in Table 1.

Embodiment 4 FIG. A recording sheet was obtained in exactly the same manner as in Example 1 except that the amount of synthetic silica used was changed to 50 parts. The results of measuring and evaluating the dynamic liquid absorbency, adhesive strength, and print quality using this recording paper are as shown in Table 1.

Embodiment 5 FIG. 50 parts of synthetic silica used,
Other than changing the amount of acetylated starch used to 110 parts,
A recording sheet was obtained in exactly the same manner as in Example 1. The results of measuring and evaluating the dynamic liquid absorbency, adhesive strength, and print quality using this recording paper are as shown in Table 1.

Comparative Example 1 A recording paper was prepared in the same manner as in Example 1 except that the amount of silica used in Example 1 was changed to 40 parts, the amount of acetylated starch was changed to 25 parts, and polyamine polyamide epichlorohydrin was not applied. Obtained. Using this recording paper, dynamic liquid absorption, adhesiveness,
The results of measuring and evaluating the print quality are shown in Table 1.

Comparative Example 2 A recording sheet was obtained in exactly the same manner as in Example 4 except that the polyamine polyamide epichlorohydrin was not applied. The results of measuring and evaluating the dynamic liquid absorbency, adhesive strength, and print quality using this recording paper are
It is as shown in Table 1.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a liquid absorption curve in a dynamic liquid absorption test.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsuyoshi Yasuda 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Inside Nippon Paper Industries Co., Ltd. Product Development Laboratory

Claims (6)

[Claims] 1. A coated paper comprising a base paper and a pseudo-adhesive layer provided on the surface of the base paper, the pseudo-adhesive layer being a water-based ink on the surface and / or inside of the layer. A pseudo-adhesive recording paper, which is a recording layer containing a fixing agent for fixing the dye therein. 2. The pseudo-adhesive recording paper according to claim 1, wherein the fixing agent is a cationic water-soluble polymer and / or a cationic water-soluble oligomer. 3. The fixing agent is at least one selected from the group consisting of polyethyleneimine quaternary ammonium salt derivative, polyamine polyamide epichlorohydrin, cationic polyvinyl alcohol, and cationic starch. The pseudo-adhesive recording paper described in 2. 4. In a dynamic liquid absorption test of a recording layer using a liquid having an interfacial tension of 35 dyne / cm under an experimental condition of 20 ° C. and 65% RH, a liquid transfer amount when a contact time is 75 msec. The pseudo-adhesive recording paper according to any one of claims 1 to 3, which has a volume of 10 to 30 ml / m ² . 5. A dynamic absorption test of a recording layer using a liquid having an interfacial tension of 35 dyne / cm under an experimental condition of 20 ° C. and 65% RH, an absorption coefficient of 1.4 to 3.0 ml ■ ・ ml ^-2・ Ms
The recording paper which can be pseudo-adhesive according to any one of claims 1 to 4, which is ec ^-1/2 . 6. The dynamic wetting test of a recording layer using a liquid having an interfacial tension of 35 dyne / cm under an experimental condition of 20 ° C. and 65% RH, the wetting time is 100 msec or less. The pseudo-adhesive recording paper according to any one of 5 above.