JPH074963B2 - Inkjet recording paper - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ink jet recording paper, and more specifically, in an ink jet recording system using a water-based ink, the color of ink absorbed and adhered in a sheet structure is clear. In addition, the present invention relates to an ink jet recording sheet that can give a sharp image with a circular dot shape and can record a high-resolution image at high speed.

[Conventional technology]

In the ink jet printer, in order to obtain a high-quality print image, the ink that has adhered to the surface of the recording paper does not spread irregularly on the surface, but has a perfect circular dot shape and is absorbed quickly. It is important to use such a base material and to have a layered structure that reinforces the color development of the adhered ink, and various means have been proposed in the past.

For example, by coating a pigment such as silica with a binder on one side of paper, the whiteness and transparency of silica can be utilized to improve the color developability and liquid absorbability of ink as compared with plain paper. For example, there is also a report (Japanese Patent Publication No. 60-27588) of coated paper using low-sized and non-sized paper having a Steckigt sizing degree of 1 second or less as a base paper.

However, since such a coated paper has a coating layer containing silica as the main component on the surface, the natural feeling of the paper is impaired, and the suitability for use such as the surface strength and the paper-passing property also becomes a problem. It is not well-received for use as office paper, and thus uncoated ink jet recording paper has been used conventionally.

[Problems to be solved by the invention]

In producing uncoated high-quality ink jet paper, it is known to add absorptive pigments such as silica at the time of papermaking, or to make non-sized paper with a sizing agent added. Has been. However, in non-size ink jet recording paper with these pigments added internally, the ink is widely absorbed in the paper layer and is blocked by the pulp and pigment, so that the sharpness and density of color development in the ink-adsorbed layer are high. In many cases, the dot spread and the shape are irregular and vague, and it is not possible to obtain a clear print image comparable to the coating type in which the surface layer selectively absorbs ink.

Further, when a relatively large amount of water-absorbing pigment is internally added, the papermaking process is also unstable, and the irregular distribution of the resulting pigment in the paper layer causes unevenness or variation in image / color formation. There is a fear that it may cause troubles during use such as paper dust generation.

The present invention, in an ink jet recording system using a water-based ink, absorbs the water-based ink promptly on the surface,
Since the color of the image produced by the ink is vivid and the ink dot shape is circular, it is possible to reproduce an image with sharp edges, and thus to record a high-resolution image at high speed. Provided is an ink jet recording sheet using a preferable internal addition sizing agent having a sizing degree within a specific range capable of eliminating the defects of the coating type, the internal addition type and the non-size type, which are the above-mentioned conventional techniques. The purpose is to do.

[Means for solving problems]

The present inventors have conducted various studies to eliminate the above-mentioned drawbacks of the prior art, and as a result, 70 to 95% by weight of wood pulp and 5 to 30% by weight of a pigment containing light calcium carbonate as a main component are contained as main components. Inkjet printer paper consisting of the following paper, the Steckigt sizing degree at a basis weight of 64 g / m ² is 6 seconds or more and 25 seconds or less, and polyethyleneimine or diallyldimethylammonium chloride copolymer is used as an internal sizing agent. By using an alkyl ketene dimer with a cationic synthetic high molecular weight substance as a fixing agent at a ratio of 0.05 to 0.5 g / m ² , water-based ink is adsorbed on the surface of the sheet to develop color, which is similar to general fine paper. Inkjet essence that enables quick ink absorption, clear coloring of ink dyes, and precise dot reproduction required for inkjet recording paper while maintaining the manufacturing method and appearance. It was found that the recording sheet can be obtained.

In the ink jet recording paper of the present invention, 5 to 30% by weight of a pigment such as light calcium carbonate is added to 70 to 95% by weight of wood pulp.

As the wood pipe, an ordinary papermaking pulp produced by bleaching a natural wood pipe is suitable.

Further, the pigment for internal addition is light calcium carbonate having a high oil absorption and a high specific surface area, especially a secondary particle diameter of 0.5 to 1.5.
Although prismatic calcite having a μm of 70% or more and an oil absorption of 10 to 80 ml / 100 g or more is preferable, other white pigments may be used in combination according to the purpose. These white pigments include commonly used fillers such as kaolin, clay, talc, diatomaceous earth, aluminum hydroxide, titanium dioxide,
Organic pigments (plastic pigments), Zeorex,
Examples thereof include silica.

Even if light calcium carbonate is not added, it is possible to obtain a certain effect by adjusting the sizing degree, but it is possible to improve the dot shape by adding light calcium carbonate within the above range. . If the amount of the pigment such as light calcium carbonate added is 5% or less, no substantial improvement effect can be seen. On the other hand, the addition of 30% by weight or more may cause quality problems such as a decrease in color density, impairing the feeling of natural paper, and generation of paper dust.

The ink jet recording paper of the present invention must have a Steckigt sizing degree of 6 to 25 seconds at a basis weight of 64 g / m ² . If it is lower than 6 seconds, water resistance is insufficient, strike-through occurs, and ink spreads irregularly.

Up to now, an alkyl ketene dimer using a cationic starch as a fixing agent and / or a dispersant has been used as an internal filler sizing agent in a general neutral papermaking process. However, in the present invention, a cationic synthetic polymer material composed of polyethyleneimine or diallyldimethylammonium chloride copolymer is used as a dispersant, and by using an alkyl ketene dimer sizing agent, a high ink dot color density and a perfect circle are obtained. Sex could be realized.

Examples of the cationic synthetic polymer substance are 1) a copolymer of a cationic surfactant having a polymerizable functional group or a polymerizable cationic monomer and a nonionic monomer, or 2) a polymerizable cationic Examples thereof include polymers of monomers.

The cationic surfactant having a polymerizable functional group is, for example, a quaternary ammonium salt having a hydrocarbon group having 4 to 28 carbon atoms represented by diallyldimethylammonium chloride and the like, which is polymerized in acrylic acid or methacrylic acid. A cationic surfactant having good properties can be exemplified. In the present invention, a diallyldimethylammonium chloride copolymer is used. The copolymerizable nonionic monomer includes, for example, a highly polymerizable monomer represented by acrylamide.

The polymer of the polymerizable cationic monomer is, for example, polyethyleneimine.

As the alkyl ketene dimer, all known ones can be used.

Next, a method for manufacturing the ink jet recording paper of the present invention will be described.

In producing the ink jet recording paper of the present invention, a usual papermaking process can be used using the above pulp and pigment, but synthetic fibers and synthetic pulp having high whiteness can also be used in combination. . Paper strength enhancers, retention aids, wet paper strength enhancers, dyes, etc., which are added as additives in papermaking, can also be used. Paper thickness is 20 ~ 200
[mu] m, and the basis weight is preferably ²⁰ to 180 g / m < ² >. Since an ink jet printer requires a sheet having good surface smoothness, it is preferable to set the Beck smoothness to 30 seconds or more by machine calendering or super calendering.

〔Example〕

 Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 Fillers and additives were added to 100 parts of bleached kraft pulp beaten for 20 minutes in a beater.

〔Additive〕

Filler: Light calcium carbonate (manufactured by Albafil Pfizer) 10 parts Sizing agent (alkyl ketene dimer) 0.05 part Fixing agent (polyethyleneimine) 0.02 part Paper strength enhancer POLYSTRON 705 Arakawa Chemical Co., Ltd. 0.2 part Retention aid 0.05 part ( Percoll 57 Allied Colloid) The 0.03% concentration papermaking raw material obtained by diluting the above with water was used to make high-quality paper using a Fourdrinier cylinder paper machine. Polyvinyl alcohol with 88% saponification (GH17
A 4% strength solution of Nippon Synthetic Chemical Industry Co., Ltd. was size press coated at a rate of 1 g / m ² to prepare the following ink jet recording paper.

Ash (calcium carbonate) 8.5% Basis weight 64 g / m ² Steckigt sizing degree 7 seconds Example 2 By the same operation as in Example 1, a paper was prepared with the following paper ingredient components.

[Additives] Filler: Light calcium carbonate (manufactured by Shiraishi Chemical Co., Ltd.) 40 parts Sizing agent: Alkyl ketene dimer 0.08 part Fixing agent: 0.02 part Acrylamide / diallyldimethylammonium chloride copolymer (PAS-J11 Nittobo) Paper strengthening agent 0.2 parts (Polystron 705, manufactured by Arakawa Chemical Co., Ltd.) Retention aid 0.05 parts (manufactured by Percoll 57 Allied / Colloid) Similarly, polyvinyl alcohol was applied to the paper made at the rate of 1 g / m ² in size breath, and the following inkjet recording was performed. I made a paper.

Ash content (calcium carbonate) 20% Basis weight 64 g / m ² Steckigt sizing degree 10 seconds Example 3 Fine paper was made into paper by the same method as in Example 1, and the ink was not subjected to size press treatment. Created a jet recording paper.

Ash content (calcium carbonate) 8.5% Basis weight 64 g / m ² Steckigt sizing degree 10 seconds Comparative Example 1 Paper was made into paper by the same method as in Example 1 with the following paper ingredients.

〔Additive〕

Filler: Light calcium carbonate (Albafil Pfizer) 10 parts Sizing agent: Alkyl ketene dimer 0.01 part Fixing agent Cationic starch (CATO-F Oji National): 1.0 part Paper strengthening agent (Polystron 705 Arakawa Chemical Co., Ltd.) 0.2 parts Retention aid 0.05 parts (Percoll 57 Allied / Colloid) Polyvinyl alcohol was similarly applied to the paper on which paper was made at 1 g / m ²
The following ink jet recording paper was prepared by applying size press coating at a ratio of.

Ash content (calcium carbonate) 8% Basis weight 64 g / m ² Steckigt sizing degree 2 seconds Comparative Example 2 A paper was prepared in the same manner as in Example 1 with the following paper ingredient components.

〔Additive〕

Filler: Light calcium carbonate (PC Shiraishi Chemical Co., Ltd.) 40 parts Cationic starch (CATO-F Oji National Co., Ltd.) 1.0 part Paper strength enhancer (Polystron 705 Arakawa Chemical Co., Ltd.) 0.2 parts Retention aid 0.05 parts (Percoll 57 allied (Made of colloid) Polyvinyl alcohol was also applied to the paper made in the same manner at 1 g / m ²
The following ink jet recording paper was prepared by applying size press coating at a ratio of.

Ash content (calcium carbonate) 18% Basis weight 64 g / m ² Steckigt sizing degree <1 second The evaluation as ink jet paper in these cases is shown in the table. The ink jet printer suitability was evaluated by using a commercially available ink jet printer for ink absorbency, dot shape, and color development.

For the evaluation of ink absorbency, a method was used in which the time (seconds) until the ink bleeding on the print spot was dried.

Regarding the shape of the dots, the print dots on the paper by the ink jet printer were observed with a microscope. The circles with a shape closer to a perfect circle are indicated by ○, △, and ×. Color development was visually evaluated.

[Advantages of the Invention] The ink jet paper of the present invention has excellent ink absorbency, dot shape, and color development, and enables a high-resolution, high-speed ink jet printer that overcomes the conventional drawbacks. It is a thing.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahiro Nakagawa 1-10-6 Shinonome, Koto-ku, Tokyo Inside the Product Research Laboratory, Oji Paper Co., Ltd. (72) Kenji Hota 1-10-6 Shinonome, Koto-ku, Tokyo No. Oji Paper Co., Ltd. Product Research Laboratory (56) References JP-A-60-109894 (JP, A) JP-A-61-16885 (JP, A)

Claims (2)

[Claims] 1. A cationic synthetic high molecular substance comprising 70 to 95% by weight of wood pulp and 5 to 30% by weight of a pigment containing light calcium carbonate as a main component and comprising polyethyleneimine or diallyldimethylammonium chloride copolymer. And an alkyl ketene dimer, wherein the Steckigt sizing degree at a basis weight of 64 g / m ² is 6 seconds or more and 25 seconds or less. 2. An alkyl ketene dimer containing 0.05 to 0.5 g / m ²
The inkjet recording paper according to claim 1, wherein the inkjet recording paper is included in the following ratio.