JPH04182184A - Ink jet paper containing deinked old paper pulp - Google Patents

Abstract

PURPOSE:To utilize regenerated paper prepared using a large amount of deinked old paper regenerated pulp, receiving ink in its paper layer, rapidly absorbing ink and developing a sharp color in the field of ink jet recording paper by removing a long fiber component from deinked regenerated pulp and further providing a coating layer based on a water-soluble high-molecular substance on the surface of base paper. CONSTITUTION:A coating layer based on a water-soluble polymer is provided on the surface of base paper consisting of 100 pts.wt. of pulp and 30-100 pts.wt. of deinked regenerated pulp with long fiber content of 0.1wt.% or less and containing 2-50 pts.wt. of a filler in a ratio of 0.5-5g/m<2> to form regenerated paper whose Stockigt sizing degree is 0.5-20sec based on a basis wt. 64g/m<2>. As the filler, light calcium carbonate is pref. and, as the water-soluble polymer, starch, polyvinyl alcohol, casein and a derivative thereof are designated and it is most pref. to add polyvinyl alcohol whose saponification degree is 90% or more in an amount of 30% or more by wt. of the solid of the coating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to inkjet paper. For more details,
The present invention is used for inkjet printers that use water-based ink, and the ink has vivid colors, provides sharp prints and images, dries quickly, and has the same feel and usability as conventional plain paper, while being recycled. Regarding inkjet paper using resources.

[Conventional technology]

In the inkjet recording system, in order to obtain high-quality prints and images, there is a means for the ink to be quickly absorbed without spreading it irregularly on the surface of the paper, and a surface structure that reinforces the coloring of the attached ink. Many proposals have been made in the past regarding means for achieving this.

For example, by applying a pigment such as silica to one side of paper together with a binder, it is possible to take advantage of the whiteness and transparency of silica to improve the color development and absorbency of ink. In this case, as the base paper for coating, a paper with a high degree of sizing may be used, and a paper with a low degree of sizing such as a low size paper with a Steckigt size of 1 second or less or no size paper may be used. (Special Publication No. 1-27588).

Furthermore, for general printing paper applications, high-quality paper or uncoated paper is used due to suitability issues such as surface strength and paper passing properties.

As uncoated inkjet paper, it is known that a liquid-absorbing pigment such as silica is added internally during paper making, or that no sizing agent is added, and paper of no size or low size is used.

Acidic paper, alkaline paper, or neutral paper is used in both coated and non-coated inkjet paper types.

On the other hand, due to the problem of resource depletion, when so-called recycled paper that uses a large amount of deinked waste paper recycled pulp is used as inkjet paper, there is a problem in that printing quality is significantly reduced. In other words, paper whose main component is deinked waste paper recycled pulp has poor suitability for inkjet printing, resulting in the so-called
``I couldn't avoid problems such as blurring.''

[Problem to be solved by the invention]

In an inkjet recording system using water-based ink, the present inventor has developed a method to improve the quality of paper using pulp and pigment as filler in order to use recycled paper that uses a large amount of deinked waste paper recycled pulp as non-coated inkjet paper in an inkjet recording system using water-based ink. We investigated the basic issue of the influence of physical and chemical properties, especially ink absorption performance, on images, removed the long fibers in the deinked recycled pulp, and added a water-soluble polymer substance to the surface of the base paper. The present invention was completed by discovering that problems such as "whisker J", "blurring J" or "blurring" can be solved by providing a coating layer containing the main component.

Therefore, the object of the present invention is to eliminate the need for an ink-receiving layer containing pigments, that is, ink reception is performed in the paper layer, and rapid ink absorption and vivid color development are obtained, and high-quality printing and image reproduction are achieved. To provide an inkjet recording sheet that can be used in the inkjet recording paper field using recycled paper that uses a large amount of deinked waste paper recycled pulp.

[Solve the problem. means for

The present invention has a long fiber content of 0 per 100 parts by weight of pulp.
．． 0.5 to 0.5 to 100 parts by weight of a coating layer mainly composed of a water-soluble polymer is applied to the surface of a base paper containing 30 to 100 parts by weight of deinked pulp of 1% by weight or less and 2 to 50 parts by weight of filler. 5g
/m2, and has a Steckigt sizing degree of 0.5 to 20 seconds based on a basis weight of 64 g/m2.

The deinked waste paper pulp used in the present invention is obtained by subjecting old newspapers, high-quality waste paper such as leaflets, etc. to a known deinking treatment, bleaching with an oxidizing bleach such as hydrogen peroxide as necessary, and then using a known screening screen. The long fibers on the 3mrnJJ were almost completely removed or disappeared by cutting and beating.

These long fibers of 3 mm or more originate from softwood-based mechanical pulp contained in waste paper, and are contained in waste paper pulp in excess of several percent. Its presence is undesirable because it causes blurring and blurring.

In the present invention, 30 to 100 parts by weight of deinked waste paper pulp is used per 100 parts by weight of the pulp used, but if the amount is 30 parts by weight or less, even if waste paper pulp is used, the effect is not significant, and the present invention It is not necessary to apply.

The virgin pulp used in the present invention includes cellulose pulp made from natural wood, usually bleached kraft pulp produced by multistage bleaching of softwood and hardwood kraft pulps, and is appropriately selected and used.

The filler used in the present invention is preferably light calcium carbonate, but general paper fillers such as clay, talc, diatomaceous earth, aluminum hydroxide, titanium dioxide, zeolex, and silica can be mentioned.

The paper base material for the present invention is manufactured by wet paper making using a known Fourdrinier paper machine, short length paper machine, etc., and drying using a Yankee dryer, multi-barrel dryer, etc. Common papermaking chemicals such as paper strength agents, retention aids, wet strength agents, and dyes are used.

In the present invention, ink reception is performed in the paper layer, and an ink reception layer such as a pigment coating layer is not required, and ink absorption is controlled by sizing. The Steckigt sizing degree is in the range of 0.5 seconds to 20 seconds, preferably in the range of 1 to NO seconds, based on a basis weight of 64 g/m2.

The water absorption of such non-coated paper is achieved by maintaining the Steckigt sizing degree within a certain range by increasing or decreasing the amount of sizing agent added, and by applying a coating layer mainly composed of a water-soluble polymer using a blade coater, size press, or It is applied using a roll coater or the like, and controlled by increasing or decreasing the amount of coating.

Water-soluble polymers include starch, polyvinyl alcohol,
Examples include natural or synthetic substances such as casein and its derivatives, and the solid content of the coating layer is 50% by weight or more, preferably 60% by weight or more.
It is added so as to include more than % by weight. Most preferably, nopolyvinyl alcohol with a saponification degree of 90% or less is added in an amount of 30% by weight or more of the solid content of the coating layer, so that the drying properties of the ink are good, the penetration and spreading of the ink is appropriate, and
Inkjet paper with clear prints and images can be obtained.

In the present invention, a water-soluble cationic polymer is added in an amount of 2 to 25% by weight based on the solid content of the coating layer to make the water-based ink image waterproof. If the water resistance agent is less than 2% by weight, the water resistance of the ink image will be insufficient, and if it is more than 25% by weight, the effects will reach a plateau, leading to an increase in cost, which is not preferable.

The coating layer is applied onto the base paper in an amount of 0.5 to 5 g/m2, but if the coating amount is more than 5 g/m2, the coating layer becomes too thick and hard, and the feel of plain paper is poor, so it is preferable. do not have. On the other hand, if the coating amount is too thin, such as less than 0.5 g/m2, it is undesirable because it becomes difficult to obtain clear color development of the ink and high resolution due to the regular dot shape.

Further, the thickness of the sheet is determined by the running properties of the print and the final use, but it is preferably in the range of 20 to 200 μm and the basis weight is in the range of 20 to 180 g/m 2 . When a sheet with good surface smoothness is required for an inkjet printer, it is preferable to subject the coated paper to machine calendering and supercalendering to achieve Oken type smoothness of 30 seconds or more.

According to the present invention, a large amount of deinked waste paper pulp can be produced by removing long fibers of 3 mm or more contained in the deinked waste paper pulp and providing a coating layer containing a water-soluble polymer as a main component on the surface of the paper base material. You can obtain inkjet paper that eliminates the problems of ``whiskers'' and ``blurring'' used in .

〔Example〕

EXAMPLES The present invention will be described in more detail with reference to Examples below, but the present invention is of course not limited thereto.

In the following, all parts and % indicate parts by weight and % by weight.

Example 1 100 parts of water was added to light calcium carbonate (Albafil, manufactured by Ryo Iser) 10B as a filler, mixed in a high-speed disperser, and then refined in a refiner for 20 minutes to obtain Freeness 450-C, S, F, ( 20 parts of bleached hardwood kraft pulp (Canadian Standard Freeness), 70% recycled newspaper
, 68% whiteness made from 30% high-quality recycled paper such as leaflets.
Waste paper pulp is screened to remove long fibers of 3 mm or more (Freeness 170m1C, S,
A papermaking raw material prepared by adding 0.05 parts of a neutral sizing agent (Fine Plan, manufactured by Tamago National Co., Ltd.), 1 part of cationic starch, and 5.0 parts of sulfuric acid to 80 parts of Fi was processed in a Fourdrinier multi-tube paper machine. 64 g/m2 paper is made, and 4 g/m2 is applied to the front and back sides of the base paper using a size press.
m2 of oxidized starch (Tamago Ace A, manufactured by Tamago Cornstarch Co., Ltd.) was applied and dried to obtain inkjet paper.

The Steckigt size degree was 10 seconds.

Example 2 3 g/each of the following paints were applied to the front and back sides of the base paper.
An inkjet paper was obtained in the same manner as in Example 1 except that the coating was applied using a m'' size press and dried.

The Steckigt size degree was 8 seconds.

Paint (solid content 10%) Oxidized starch 50% Polyvinyl alcohol 50% (manufactured by 217 Kuraray) Salt
5% Comparative Example 1 An inkjet paper was obtained in the same manner as in Example 1 except that deinked waste paper pulp without removing the long fiber portion was used.

The Steckigt size degree was 10 seconds.

Comparative Example 2 An inkjet paper was obtained in the same manner as in Example 1 except that 4 g/m2 of oxidized starch was not applied to the front and back sides of the base paper.

The Steckigt size degree was 6 seconds.

Table 1 shows the evaluation results regarding the recording performance of the inkjet paper obtained in Example 1 to Comparative Example 2.

The recording performance of this inkjet paper was evaluated using a commercially available inkjet printer (Canon WBJ 1).
30 J), and the ink absorbency (indicated by the time required for the ink to dry) and print quality were evaluated.

The evaluation was performed visually, and the results were indicated by markings ◎, ○, △, and mouth in order of best.

As is clear from Table 1, the inkjet paper of the present invention has excellent ink absorption and printing quality;
If the long fibers contained in the deinked waste paper are not removed, even if a water-soluble polymer adhesive layer is provided on the surface of the base paper (Comparative Example 1),
Ink absorbency and printing quality are poor (especially when hairs appear (Comparative Example 2); ink absorption is excellent but printing quality is poor (especially blurring occurs) [Effects of the Invention] The inkjet of the present invention Paper has excellent ink absorption and printing quality, and it eliminates the drawbacks of conventional paper, making it possible to use recycled paper in inkjet printers, and contributing greatly to the industry.

Patent applicant: Oji Paper Co., Ltd.

Claims (1)

[Claims] 1. A highly water-soluble, highly water-soluble The coating layer whose main component is molecules is 0.5 to 5 g/m^2
The Steckicht sizing degree is set at the ratio of 64g basis weight.
An inkjet recording paper characterized in that the time is 0.5 to 20 seconds on a /m^2 basis.