JP2002127592A - Multilayer papermaking ink jet sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer papermaking ink jet sheet of single-side coating for obtaining good print quality even by writing with water base ink at a non-coating surface side with high printing quality of an ink acceptive layer. SOLUTION: The multilayer papermaking ink jet sheet comprises the ink acceptive layer containing a pigment as a main body and provided on one surface side of multilayer papermaking base paper, and the base paper having no coated layer thereon and provided on the opposite surface side of the base sheet without providing an ink acceptive layer containing the pigment as the main body. In this case, an absorption amount of water from the side provide with the ink acceptive layer is 20 g/m2 or more of a value calculated as (g) number per 1 m2 by measuring a weight of water absorbed from the ink acceptive surface, by contacting the layer with the ink acceptive surface of a predetermined area for 5 s at 20 deg.C by using water and removing excess liquid by blotting paper. An absorption amount of water of the bare surface of the base paper is 15 g/m2 or less without providing the ink acceptive layer of an opposite side of the base paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-side coated multi-layer inkjet paper having a pigment-based ink-receiving layer formed on one side of a base paper, and having high print quality, high ink absorbency, and postcard. And card paper.

[0002]

2. Description of the Related Art In an ink jet recording system, fine droplets of ink are made to fly by various ejection systems and adhere to a recording medium such as paper to record images, characters, and the like. High-speed, low-noise, easy multi-color printing is rapidly spreading as a recording device for color images and the like.

The recording medium used in this ink jet recording system has a high density of ink dots, a bright and vivid color tone, and ink does not flow or bleed even when multicolor ink dots overlap. Fast ink absorptivity and good transportability in printers are required. Several proposals have hitherto been made to satisfy these requirements.

JP-A-55-5830 discloses an ink-jet recording sheet having an ink-absorbing coating on the surface of a support, and JP-A-55-11829 discloses a two-layer structure having different ink-absorbing speeds. A coated paper having the formula: Further, Japanese Patent Publication No. 6-55542, No. 2618
In the publications of the '359 patent and the' 2618358 patent, the amount of the aqueous solution obtained by mixing various solvents permeating the recording paper in an arbitrary time is specified to improve the quality. Japanese Patent Publication No. 6-55542 specifies the permeation amount of an aqueous solution in which the ratio of polyethylene glycol having a degree of polymerization of 400 and water is 1: 1. Japanese Patent No. 2618359 and Japanese Patent No. 2618358 specify the permeation amount of a 30% by weight aqueous solution of diethylene glycol at an arbitrary contact time.

[0005] In a single-sided coated inkjet paper, a color photograph, a color picture, and the like are printed on a surface having an ink receiving layer (hereinafter referred to as a printing surface) by an inkjet printer. On the other hand, the other side (hereinafter referred to as uncoated side) is not coated, the base paper is exposed, and the address is written with a ballpoint pen, pencil, brush, magic ink, etc. It is sometimes done. When multicolor printing is performed on a printing surface with an ink jet printer, it is desirable that the bump absorbency in a short time such as a contact time of 5 seconds is high. In other words, the absorption speed of inkjet ink is high, and even when multicolor printing is performed at high speed, there is no stain due to ink transfer to another paper when printed matter is overlaid, and multicolor printing Bleeding at the boundary of the image is also reduced.

On the other hand, a ballpoint pen, a pencil, a brush,
In the case of an ink jet printer for writing with magic ink or printing only black characters, it is desirable to reduce the water absorption of bumps. When the water absorption of the bump is high, a character called a feathering occurs in a ballpoint pen, a writing brush, or a magic ink using an aqueous ink, or a feathering occurs in an ink jet printer.

[0007] Therefore, in the conventional single-layer paper-coated single-sided ink-jet paper, a design has been made to increase the water absorption on the printing surface side and to reduce the water absorption on the non-coating surface side. However, especially in order to give priority to the quality on the printing surface side, a trace amount of an internally added sizing agent has been added in the base paper formulation.

In such a case, as means for lowering the water absorption of the bumps on the non-coated side, a surface size represented by an alkyl ketene dimer (AKD) or a styrene-acrylic size may be used only on the non-coated side. Coating has been done. However, only by performing such a surface treatment on the non-coated surface side, a satisfactory bump water absorption value could not be obtained.

[0009] In addition, good transportability in a printer is required for ink-jet paper, but the transportability depends on the surface treatment of the non-coated surface. When the surface sizing agent is used frequently, it is liable to slip due to its characteristics or to make it difficult to slip, consequently a double feeding trouble in which two sheets are fed together and a misfeed in which the paper does not enter the printer.

Japanese Patent Application Laid-Open Nos. Hei 1-78877 and Hei 9 are examples of using multilayer papermaking as ink jet paper.
No. 143900 and Japanese Patent Application Laid-Open No. H11-105414, all of which are directed to uncoated or lightly coated ink jet paper having the texture of plain paper. The print quality was not sufficiently satisfactory as compared with the type of ink jet paper.

[0011]

According to the present invention, an ink receiving layer mainly comprising a pigment is provided on one side of a base paper, and an ink receiving layer mainly comprising a pigment is provided on the other side of the base paper. The base paper is an exposed inkjet paper without being exposed, both sides of the base paper can be printed with an aqueous inkjet printer, the printing quality of the ink receiving layer is high, and the non-coated side can be written with aqueous ink. It is an object of the present invention to provide a single-side coated multi-layer inkjet paper capable of obtaining good print quality.

[0012]

The above objects of the present invention are as follows.
Is achieved. One side of multi-layer base paper
A pigment-based ink receiving layer, and
Without providing an ink receiving layer mainly composed of pigment on the opposite side
A multi-layer inkjet paper in which the base paper is bare.
The amount of water absorbed from the side on which the ink receiving layer is provided.
Is applied to the ink receiving surface of a certain area with water at 20 ° C for 5 seconds.
Contact, remove excess liquid with blotter paper,
Measure the weight of water absorbed from the receiving surface and measure 1m²Hit
Is 20 g / m²Above
The base paper is exposed without providing the ink receiving layer on the opposite side of the base paper
15 g / m of water absorption on the surface ²Multilayer paper with
Inkjet paper.

The structure of the multi-layered base paper is such that, on the side where the ink receiving layer is provided, the internal sizing agent is 0 to 0.03% by weight with respect to 100 parts by weight of the pulp. 2. The multi-layered inkjet paper according to claim 1, wherein the side of the base paper that is exposed without providing the ink receiving layer contains 0.1% by weight or more of an internal sizing agent.

3. The multi-layer inkjet paper according to claim 1, wherein the pigment-based ink receiving layer has a dry coating amount of 7 to 13 g / m ² .

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the present invention, a pigment-based ink-receiving layer is provided on one side of the multilayered base paper, and the pigment-based ink-receiving layer is not provided on the other side of the base paper. Is the exposed inkjet paper, the amount of water absorbed from the side provided with the ink receiving layer is determined by contacting the ink receiving surface with a constant area at 20 ° C. for 5 seconds with water to absorb excess liquid. , The weight of water absorbed from the ink receiving surface was measured, and the value calculated as the number of grams per 1 m ² was 20.
g / m ² or more, and the water absorption amount of the exposed surface of the base paper without providing the ink receiving layer on the opposite side was 15 g / m ² or less. .

That is, if the amount of water absorbed from the side on which the ink receiving layer is provided is 20 g / m ² or more, even when multicolor ink is printed at a high speed by an ink jet printer, the ink absorption is fast, and this is called offset. No symptoms occur. On the other hand, if the water absorption is less than 20 g / m ² , a phenomenon called set-off is likely to occur, which is not preferable. The amount of water absorbed from the side provided with these ink receiving layers can be controlled by a combination of a base paper formulation and a color formulation,
Particularly, the amount of the internal sizing agent added to the base paper on which the ink receiving layer is provided is important.

More preferably, an absorption amount of an aqueous ethanol solution (using a solution having a weight ratio of ethanol: water of 25:75, brought into contact with an ink receiving surface having a constant area at 20 ° C. for 5 seconds,
Excess liquid is removed with blotting paper, the weight of water absorbed from the ink receiving surface is measured, and the value (calculated as the number of grams per 1 m ² ) is adjusted to 50 g / m ² or more. When the absorption amount of the aqueous ethanol solution is 50 g / m ² or more, the ink absorbency and the boundary bleeding of each color ink can be further improved.

The amount of ethanol aqueous solution absorbed is affected by both the absorbency of the base paper and the absorbency of the ink receiving layer.
It is necessary for the base paper to have a more porous structure, and as a specific means, it is effective to increase the degree of beating of the wood pulp used as a raw material. Normal CSF
Is adjusted to 400 cc or more.

The reason why the water absorption amount of the uncoated surface where the base paper is exposed without providing the ink receiving layer on the opposite side was 15 g / m ² or less was written especially with an aqueous ink such as a fountain pen or ink. This is to prevent bleeding in the case. 15 g of water absorption
/ M ² is not preferable because bleeding occurs. On the other hand, in consideration of printing with an ink jet printer, a preferable range is 5 to 15 g / m ² . In this case, printing is usually performed using a single color ink. However, if the printing is performed using an inkjet printer at less than 5 g / m ² , the absorbency becomes poor. The amount of water absorbed on these uncoated surfaces can be adjusted to some extent by applying a surface sizing agent, but adverse effects such as poor transportability in a printer are also likely to occur,
The amount of the internal sizing agent added on the non-coated side is important.

The side on which the ink receiving layer is provided is pulp 100
The internal sizing agent is contained in an amount of 0 to 0.03% by weight based on part by weight. When talc is used as the filler, a reinforced rosin sizing agent or the like is used as the internal sizing agent, and when calcium carbonate is used as the filler, a neutral rosin sizing agent, ASA, AKD, or the like is used. If the amount of each sizing agent exceeds this range, the amount of water absorbed on the coated surface will be less than 20 g / m ² , and a phenomenon called set-off is likely to occur, which is not preferable.

On the other side, the uncoated side where the base paper is exposed without providing the ink receiving layer, the internal sizing agent is contained in an amount of 0.1% by weight or more based on 100 parts by weight of the pulp. When talc is used as a filler, a reinforced rosin sizing agent or the like is used as an internal sizing agent. When calcium carbonate is used as a filler, a neutral rosin sizing agent, ASA, AKD is used.
Are used. 0.1% by weight of each sizing agent
If less than 15 g / m ²
And bleeding of the aqueous ink or the like is apt to occur, which is not preferable.

The ink receiving layer mainly composed of a pigment has a dry coating amount of 7 to 13 g / m ² . When the amount of the ink receiving layer mainly containing a pigment is less than 7 g / m ² , the ink bleeds and the color developability in the ink jet multicolor printing are not preferable. If the pigment-based ink receiving layer exceeds 13 g / m ² ,
The color development represented by the print density is reduced, and the pigment is remarkably dropped from the ink receiving layer, which undesirably stains the transport roll of the printer.

The preferred embodiment of the recording material used in the present invention will be specifically described below. The base paper used in the present invention is a multilayer paper.
-Use wood pulp represented by BKP and N-BKP. Recycled paper pulp can be appropriately blended. In the stock, a paper strength agent, a filler, a band, a retention aid, a dye, a fluorescent dye, and the like are appropriately used. Cationic starch as paper strength agent,
Polyacrylamide is used. As the filler, calcium carbonate, talc, clay, synthetic zeolite, calcium silicate, titanium and the like are used. Colloidal silica, polyacrylamide, polyethyleneimine, or the like is used as the yield improver. Dyes and fluorescent dyes are added to adjust the hue of paper, and direct dyes, basic dyes, acid dyes and the like are used.

When calcium carbonate is used as a filler as a sizing agent in the paper stock, an alkyl ketene dimer (A
KD), alkenyl succinic anhydride (ASA), neutral rosin and the like are used, and for fillers other than calcium carbonate, fortified rosin and saponified rosin are mainly used. The amount of sizing agent added to the stock is limited to the outermost layer of the base paper on which the ink receiving layer is provided.
No addition or trace addition. The sizing agent may be added to the other layers as appropriate, but the amount of the sizing agent added to the outermost back surface where the base paper is exposed without providing the ink receiving layer is adjusted so as to reduce the water absorption.

The papermaking of the base paper is carried out by using a round papermaking machine or a fourdrinier papermaking machine and at least two or more layers by using the above-mentioned stock. In the middle of the process, the product may be passed through a device that applies a coating solution such as starch, polyvinyl alcohol, and a surface sizing agent, such as a size breath and a gate roll. The amount of surface sizing agent applied must be adjusted to satisfy the absorption.

The application of the ink receiving layer to the base paper is carried out by applying the ordinary ink receiving layer on a separate coating line irrespective of the paper machine. However, the coating is carried out simultaneously with the formation of the base paper on the paper machine. It is also possible. The coating liquid for obtaining the ink receiving layer is not particularly limited, but is prepared from a porous inorganic pigment, an adhesive, and a waterproofing agent. Synthetic silica is used as the porous inorganic pigment, and alumina, light calcium carbonate, heavy calcium carbonate, kaolin clay, talc, calcium silicate, satin white, and the like may be used in some cases.
As the adhesive, oxidized starch, etherified starch, cellulose derivatives such as carboxymethyl cellulose, casein,
Gelatin, soy protein, polyvinyl alcohol and derivatives thereof, styrene-butadiene copolymer, conjugated diene-based polymer latex such as methyl methacrylate-butadiene copolymer, and vinyl-based polymer latex such as ethylene-vinyl acetate copolymer. Used alone or in combination. These adhesives are used in an amount of 10 to 50 parts by weight based on 100 parts by weight of the pigment, but the ratio is not particularly limited as long as the amount is sufficient for binding the pigment. As the water-proofing agent, a cationic resin, a cationic surfactant, cation-modified inorganic particles and the like are appropriately used.

For the coating, an air knife coater is generally used, but a blade coater, a gate roll coater, a curtain coater or the like can be used. The surface of the coated recording paper is smoothed using a calender, a super calender, a raster press or the like to prevent the pigment from dropping from the ink receiving layer.

[0028]

EXAMPLES The present invention will be described in more detail with reference to the following examples. In the examples, parts and% represent parts by weight, and the amount of each addition is a solid content equivalent. The embodiment is not limited in any way. Example 1 The stock in contact with the ink receiving layer was L-BK beaten to 500 cc Canadian Standard Freeness (CSF).
4 parts of talc as a filler and 0.02 of a commercially available rosin sizing agent (Colopearl E-5H, manufactured by Seiko Chemical Co.)
% And a sulfuric acid band of 0.5% were added to prepare a slurry.
This is called a one-layer stock slurry. The stock on the opposite side, the bottom layer, is L-BKP beaten to 500 cc Canadian Standard Freeness (CSF),
A slurry was prepared by adding 4 parts of talc as a filler, 0.3% of a commercially available rosin sizing agent (Colopearl E-5H, manufactured by Seiko Chemical), and 0.5% of a sulfuric acid band. This is called a three-layer stock slurry. The other middle layer stock is 50/50 blending ratio of L-BKP beaten to 500cc Canadian Standard Freeness (CSF) and high quality waste paper.
And 4 parts of talc as filler based on the total amount of pulp,
A slurry was prepared by adding 0.3% of a commercially available rosin sizing agent (Colopearl E-5H, manufactured by Seiko Chemical) and 0.5% of a sulfuric acid band. This is called a two-layer stock slurry.

The above three kinds of stock slurries are mixed in each layer for 60 times.
paper making long network so that the basis weight of g / m ^2, and papermaking base paper comprising a base paper having a basis weight of 180 g / m ² combined Extract. A paint having the following composition is applied to the base paper thus formed on the first layer side of the base paper by an air knife coater and dried, and 10 g / m ^2.
After the ink receiving layer was provided, a super calender treatment was performed to prepare an ink jet recording sheet. The water absorption of the ink receiving layer of this ink jet recording paper was 25 g /
m ² , the aqueous ethanol absorption amount was 60 g / m ² , and the water absorption amount on the exposed side of the base paper on the opposite side was 12 g / m ² . Composition of paint: Synthetic silica Fine Seal (manufactured by Tokuyama Corporation) 100 parts Polyvinyl alcohol PVA117 (manufactured by Kuraray Co., Ltd.) 40 parts Cationic dye fixing agent Quaternary ammonium salt type polymer 10 parts

Example 2 An ink jet recording sheet was prepared in the same manner as in Example 1 except that the amount of the sizing agent added to the one- and two-layer paper stock slurry was changed to 0%. The water absorption of the ink receiving layer of this ink jet recording paper was 45 g / m ² , the aqueous ethanol absorption was 70 g / m ² , and the water absorption of the exposed base paper on the opposite side was 14 g / m ² . .

Example 3 One-layer paper slurry was 5 parts of light calcium carbonate (TP121 manufactured by Okutama Kogyo) as filler and A as sizing agent.
SA (Coropearl Z100-D, manufactured by Seiko Chemical Co.) 0.02
%Using. The three-layer paper stock slurry is 5 parts of light calcium carbonate (TP121 manufactured by Okutama Kogyo) as filler and ASA (Coropearl Z100-D manufactured by Seiko Chemical Co.) as sizing agent.
0.1% was used. The two-layer paper stock slurry was prepared by adding 5 parts of light calcium carbonate (TP121 manufactured by Okutama Kogyo Co., Ltd.) as a filler and adjusting the slurry without any sizing agent. Except for this, an ink jet recording sheet was prepared in the same manner as in Example 1. The water absorption of the ink receiving layer of this ink jet recording paper was 25 g / m ² , the aqueous ethanol absorption was 65 g / m ² , and the water absorption of the exposed side of the base paper was 14 g / m ² . .

Example 4 An ink jet recording sheet was prepared in the same manner as in Example 1 except that an ink receiving layer of 12.5 g / m ² was provided.
The water absorption of the ink receiving layer of this ink jet recording paper is 25 g / m ² , and the absorption of ethanol aqueous solution is 63 g / m ² .
^2. The water absorption of the exposed side of the base paper is 12
g / m ² .

Example 5 An ink jet recording paper was prepared in the same manner as in Example 1 except that an ink receiving layer of 8 g / m ² was provided. The water absorption of the ink receiving layer of this ink jet recording paper is 25
g / m ² , the aqueous ethanol absorption is 58 g / m ² , and the water absorption of the exposed base paper on the opposite side is 12 g / m 2
It was ² .

Comparative Example 1 Canadian Standard Freeness (CSF) 500
To L-BKP beaten to cc, 4 parts of talc as a filler and a commercially available rosin sizing agent (Colopearl E-5H)
0.02% of sulfuric acid band) and 0.5% of a sulfuric acid band were added to prepare a slurry. Using the stock slurry, a long wire paper machine was used to make a paper at 180 g / m ² , and used as a base paper. An ink jet recording paper was prepared in the same manner as in Example 1 except that this base paper was used. The water absorption of the ink receiving layer of this ink jet recording paper was 25 g / m ² , the aqueous ethanol absorption was 60 g / m ² , and the water absorption of the exposed base paper on the opposite side was 60 g / m ² . .

Comparative Example 2 The same procedure as in Comparative Example 1 was carried out except that AKD was applied to the uncoated side of the uncoated base paper of Comparative Example 1 with an air knife coater so that the absolute dry amount was 0.2 g / m ^2. To prepare an ink jet recording paper. The water absorption of the ink receiving layer of this ink jet recording paper was 25 g / m ² , the aqueous ethanol absorption was 60 g / m ² , and the water absorption of the exposed side of the base paper was 14 g / m ² . .

Comparative Example 3 An ink jet recording paper was prepared in the same manner as in Comparative Example 1 except that 0.04% of a commercially available rosin sizing agent was added.
The water absorption of the ink receiving layer of this ink jet recording paper is 18 g / m ² , and the absorption of ethanol aqueous solution is 45 g / m ² .
^2. The water absorption of the exposed side of the base paper is 16
g / m ² .

Comparative Example 4 An ink jet recording paper was prepared in the same manner as in Example 1 except that the coating amount was changed to 6 g / m ² . The water absorption of the ink receiving layer of this ink jet recording paper was 28 g / m ² ,
The absorption amount of the aqueous ethanol solution was 48 g / m ² , and the absorption amount of water on the exposed side of the base paper on the opposite side was 14 g / m ² .

Comparative Example 5 An ink jet recording paper was prepared in the same manner as in Example 1 except that the coating amount was changed to 15 g / m ² . The water absorption of the ink receiving layer of this ink jet recording paper was 22 g /
m ² , the aqueous ethanol absorption amount was 65 g / m ² , and the water absorption amount on the exposed side of the base paper on the opposite side was 14 g / m ² .

Evaluation method An inkjet printer manufactured by Canon Inc.
Printing was performed using BJC430J and photo ink. The color development of the printed surface was determined by visual inspection of the densities of cyan, magenta, yellow, and black. The bleeding on the printed surface was evaluated at the boundary between cyan and magenta, and was evaluated as ○ when no bleeding occurred, and as x when bleeding occurred. The bleeding on the uncoated surface was evaluated as ○ when no bleeding occurred and X when the bleeding occurred with a fountain pen.

The transportability of the ink jet printer is as follows.
When 100 sheets were continuously passed without any problem by BJC430J manufactured by Canon Inc., the paper was conveyed without any problem, and when the paper was double-fed or stuck on the way, it was evaluated as x. As for the dirt on the printer transport roll, 100 sheets were continuously passed through BJC430J manufactured by Canon Inc., and the case where no dirt was generated was evaluated as ○, and the case where dirt was generated was evaluated as x.

[0041]

【table 1】

[0042]

[Table 2]

[0043]

From the above results, it can be seen that the present invention has excellent print quality and bleeding on the printed surface, no bleeding on the uncoated surface, and
It is possible to provide an ink jet recording sheet suitable for postcards and cards having excellent transportability.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsutomu Sato 3-5-1 Nishi-Zao, Nagaoka City, Niigata Prefecture Inside Hokuetsu Paper Mfg. Co., Ltd. (72) Inventor Yoshihiko Ota 3-5-1, Nishi- Zao, Nagaoka City, Niigata Prefecture (72) Inventor Katsuyuki Fuse 3-2-1 Zao, Nagaoka-shi, Niigata Pref.Nagaoka Mill Co., Ltd. (72) Inventor Hiroshi Kuwano 3-5-1 Nishi-Zao, Nagaoka-shi, Niigata Pref. Inside Paper Machinery Research Laboratory (72) Inventor Yoshiyoko Fukawa 3-5-1 Nishi Zao, Nagaoka City, Niigata Pref. AG18 AG41 AG50 AG64 AH02 AH11 AH37 AH50 AJ01 AJ04 BD18 BE08 EA10 EA14 EA32 FA11 GA09

Claims (3)

[Claims] 1. An ink-receiving layer mainly composed of a pigment is provided on one side of a multi-layer base paper, and on the opposite side of the base paper,
A multi-layered inkjet paper in which the base paper is exposed without providing an ink receiving layer mainly composed of a pigment, wherein the amount of water absorbed from the side provided with the ink receiving layer is 20 ° C. using water. 5 seconds in contact with the ink-receiving surface of the predetermined area, removed in blotting paper excess liquid, the weight of water absorbed from the ink receiving surface is measured, the value calculated as g per 1 m ² is 20 g / and m ² or more, the multilayer Extract inkjet paper, characterized in that the absorption of water of the surface base paper is exposed without providing the ink-receiving layer of the base paper opposite to the 15 g / m ² or less. 2. The multi-layered base paper according to claim 1, wherein the side on which the ink receiving layer is provided has an internal sizing agent in an amount of 0 to 0.03% by weight based on 100 parts by weight of the pulp. 2. The multi-layered inkjet paper according to claim 1, wherein the other side of the base paper that is exposed without providing the ink receiving layer contains 0.1% by weight or more of the internal sizing agent. 3. The multi-layer inkjet paper according to claim 1, wherein the ink receiving layer mainly composed of a pigment has a dry coating amount of 7 to 13 g / m ² .