JPS60260377A - Ink jet recording paper - Google Patents

Abstract

PURPOSE:To enable to enhance resistance to water and light, by incorporating a cationic colloidal silica, in a recording paper comprising a fibrous substance and a filler. CONSTITUTION:For example, 20pts. of talc, 0.5pt. of cationic starch and 3pts. of cationic colloidal silica are added to a pulp slurry consisting of 80pts. of an LBK pulp having a freeness of 370ml CSF and 20pts. of an NBK pulp having a freeness of 400ml CSF, and a paper with a basis weight of 65g/m<2> is madded therefrom by a Fourdrinier paper machine while applying a 2% solution of oxidized starch in an amount of 1.5g/m<2> as solid components by a size press. Besides, when making the paper, a sizing liquid comprising 2% of polyvinyl alcohol and 1-10% of cationic colloidal silica is applied in an amount of 60g/m<2> by a size press, thereby producing a recording paper. Accordingly, water resistance is markedly enhanced, while substantially retaining the light resistance.

Description

Detailed Description of the Invention (4) Industrial Application Field The present invention relates to a recording medium recorded using ink, and in particular, a medium having a high density of images and characters recorded on the medium and a high ink absorption capacity. The present invention relates to an inkjet recording paper that has excellent properties and particularly excellent storage stability.

(Rin) Prior art and its problems The inkjet recording method uses various operating principles to fly minute droplets of ink and make them adhere to a recording medium such as paper to record images, characters, etc. , high speed, low noise, easy multi-color printing, great flexibility in recording patterns, and no need for development or fixing, making it suitable for a variety of uses as a recording device for various shapes and color images, including kanji. It is rapidly spreading in the world. Furthermore, images formed using the multicolor inkjet method can produce records that are comparable to multicolor printing using the plate making method or printing using the color photographic method, making it suitable for applications that require fewer copies to be produced. Since it is cheaper than photographic technology, it is being widely applied to the field of full-color image recording.

Efforts have been made in terms of equipment and ink composition to use high-quality paper or coated paper, which are used for ordinary printing and writing, as the recording medium used in this inkjet recording method. However, as the performance of inkjet recording devices has improved and their applications have expanded, such as higher speeds, higher definition, and full color inkjet recording devices, higher speed characteristics have become required of recording media. In other words, the recording medium must have high ink dot density, bright and colorful tones, fast ink absorption so that the ink does not run out or smear even when ink dots overlap, and ink dots that The horizontal diffusion is not larger than necessary, and the periphery is smooth and not blurred. Furthermore, it is required that the resistance of the dye when the recorded image is exposed to ultraviolet rays, oxygen in the air, or water be not reduced, but preferably increased.

Several proposals have been made to solve these problems. For example, Japanese Patent Application Laid-Open No. 52-53012 discloses an inkjet recording paper made by moistening a low-sized base paper with a paint for surface treatment.
No. 9113 discloses an inkjet recording paper in which a sheet internally added with urea-formalin resin powder is impregnated with a water-soluble polymer. These paper-type inkjet recording papers absorb ink quickly, but
The drawbacks are that the periphery of the dot tends to be blurred and the dot density is low.

Further, JP-A No. 55-5830 discloses an inkjet recording paper in which an ink-absorbing coating layer is provided on the surface of the support, and JP-A No. 55-51583 discloses a non-glue pigment as a pigment in the coating layer. An example using silica powder is disclosed, and furthermore, JP-A-55-11829 discloses an example of smear paper using a two-layer structure with different ink absorption speeds. These coated paper-type inkjet recording papers are improved over general paper-type inkjet papers in terms of dot diameter, dot shape, dot density, and color tone reproducibility, but there are Most of the inks used are water-based inks that use water-soluble dyes, and if the image formed on the recording medium is exposed to water, the dye may dissolve again and ooze out, significantly reducing the value of the recorded material. There is a problem with this.

Therefore, in order to improve this drawback, for example,
No. 5-53591 discloses an example in which a water-soluble metal salt is applied to the recording surface, and JP-A No. 56-84992 discloses an example of a recording medium containing a polycationic polymer electrolyte on the surface. JP-A No. 557150396 discloses a method of applying a water-resistant agent that forms a lake with the dye in the ink after inkjet recording, and JP-A No. 56-58869 discloses
This publication discloses a method of making a recording sheet coated with a water-soluble polymer waterproof by insolubilizing the water-soluble polymer after inkjet recording.

However, these water-fastening methods have a weak effect on water-fastening, or the water-fastening agent causes some kind of reaction with the dye, reducing the shelf life of the dye, making it impossible to achieve both sufficient water resistance and light resistance. It was quite difficult.

(C) Purpose of the Invention The present inventor has conducted various studies in order to improve the water resistance and light resistance of aqueous ink images and to obtain a recording medium capable of producing high-speed, high-definition inkjet images as described above. As a result, the above object was successfully achieved and the present invention was completed.

(D) Structure and operation of the invention In other words, the present invention provides an inkjet recording method for obtaining a recorded image by ejecting an aqueous inkjet ink onto a recording medium, wherein the recording medium is an ink comprising a fibrous substance and a filler. By containing cationic colloidal silica in the ink receptor, it has the ability to form high-density, high-definition multicolor images with excellent water resistance and light resistance for water-soluble dyes. This is the provision of recording media.

It is not clear why the inkjet recording medium containing the cationic colloidal silica according to the present invention can improve the water resistance of water-soluble dyes and also improve the light resistance. However, water-based inks containing direct dyes or acid dyes with anionic dissociative groups are often used for inkjet inks, and the ameon dye in the ink and the cationic surface of the cationic colloidal silica in the recording medium are often used. It is speculated that the ionic absorption attraction between them is involved.

Usually, colloidal silica is an anionic coid-like dispersion in which ultrafine particles of silicic anhydride (silica) are stably dispersed in water.
It is supplied to the market under brand names such as 5ytonr by Nalco Co., Ltd. and Snowtex by Nissan Chemical Co., Ltd.

There are various methods for producing these colloidal silicas, but the general method is to use an ion exchange resin, in which a sodium silicate aqueous solution is passed through a cation exchange resin to form
As a sol with a no of 60 to 130.

This is heat-ripened at 60°C or above to grow into independently dispersed particles, and then a new sol passed through an ion exchange resin layer is added to polymerize and precipitate the particles to a size of 3 nm to 200 nm.
In this method, the particles are grown to an average particle diameter of m to form a stable sol.

Silica sols have a siloxane structure, and each silica particle usually has enough negative charge (anionicity) to repel each other.

The cationic colloidal silica used in the present invention is one in which at least the surface of the silica particles is cationically charged by containing a compound of polyvalent metal ions such as aluminum ions or an organic cationic compound on or inside the silica. . In particular, colloidal silica which is totally cationized from basic aluminum is preferred according to the invention.

These products are commercially available, such as Snowtex AK manufactured by Yassan Kagaku Co., Ltd.

The content of the cationic colloidal silica in the recording medium is 0.111''/m' to 20 P/m'1, preferably 0.5?/rrl-10P/rr?, and if it is too low, it may be a water-soluble dye. The effect of water resistance is weak. Although there is no need to particularly limit the amount, the above-mentioned range is appropriate in terms of effectiveness and cost.

In the present invention, the method for incorporating the cationic colloidal silica into the recording medium is, for example, a so-called internal addition method in which cationic colloidal silica is added to a slurry in the papermaking process, or a spray device, size control method, etc. Any of the so-called post-treatment methods of applying and impregnating with a press machine, an air knife coater, a gate roll coater, a blade coater, etc. can be used.

Furthermore, in the case of post-treatment methods, it is also possible to use commonly used T-circle treatment agents such as oxidized starch or polyvinyl alcohol in combination with cationic colloidal silica.

In addition, pigments and adhesives, if necessary, pigment dispersants, thickeners, etc.
Fluidity modifier, antifoaming agent.

Foam suppressants, mold release agents, foaming agents, penetrants, colored dyes, colored pigments, optical brighteners, ray absorbers, antioxidants, preservatives, anti-piping agents, etc. can also be blended as appropriate.

Examples of fillers and pigments include calcium carbonate, kaolin (white clay), talc, calcium sulfate, barium sulfate,
Titanium oxide, zinc oxide, zinc carbonate, aluminum silicate, aluminum hydroxide, aluminum oxide, calcium silicate, magnesium silicate, non-α silica, and inorganic and organic pigments such as plastic pigments and urea resin pigments, and these It is a white pigment that is commonly used in combination with

(2) Examples Measurement of various physical property values in Examples was carried out in the following manner. First, Sharp Corporation type inkjet printers (10-
The images obtained by solid printing with cyan fc), magenta (Fc), yellow (2), and black (B)) inks using 700) were immersed in running water for 3 minutes, and the image density before and after immersion was measured. was measured using a Macbeth densitometer RD514, and the percentage obtained by dividing the concentration after immersion by the concentration before immersion was used as a measure of water resistance. In addition, a solid image obtained in the same manner was measured using a xenon fade meter (manufactured by Suga Test Instruments Co., Ltd., FAL-
25X-HCL type) at 40℃, 60%, illuminance 63W
/7i for 40 hours, and the color density before and after irradiation was measured using a Macbeth densitometer RD514, and the percentage of the density before and after irradiation was used as a measure of light resistance.

-The higher the numerical value is, the better the light resistance and water resistance are. The dot diameter was determined by measuring the area of a single dot in the black ink area of the same inkjet printer using a dot area meter, converting it to an area assuming a perfect circle, and calculating the diameter. The ink absorption speed was determined using the same color image printer by bringing the red printed area (magenta + yellow) into contact with a paper presser roll immediately after solid printing (about 1 second later), and determining whether stains appeared or not. Furthermore, the ink absorption ability was determined by the degree of bleeding at the boundary of the solid printed area using the same inkjet printer.

The present invention will be described below with reference to examples, but it is not limited to these examples. In addition, parts and percentages shown in the examples mean parts by weight and percentages by weight.

Example 1 20 parts of talc and cationic starch (Cat
oR Oji Nashi Tamagoru Co., Ltd.) 0.5 parts, cationic colloidal silica (Snowtex-AK, Nissan Chemical Co., Ltd.) 3
The basis weight is 65. P/77! ! Paper is made using a Fourdrinier paper machine, and oxidized starch (M5
3800, manufactured by Nihon Shokuhin Kako Co., Ltd.) 2% liquid with solid content of 1. s
'i-/- attached. Table 1 shows the results of evaluating the water resistance and light resistance of the recording paper thus produced.

Comparative Example 1 Comparative Example 1 was prepared in the same manner as in Example 1 except that the cationic colloidal silica was removed from the formulation of the Example. Table 1 shows the results of evaluating the water resistance and light resistance of this recording paper.

Example & 3, 4゜ Paper-making was carried out in the same manner as in Comparative Example 1, and during paper-making, 2% polyvinyl alcohol (PVA117 manufactured by Kuraray Co., Ltd.) was added using a size press machine.
, cationic colloidal silica (Snowtex-AK
A size press solution of 1%, 5%, and 10% (manufactured by Nissan Chemical Co., Ltd.) was deposited on the paper to prepare the recording paper of Example 2.3.4.

Table 1 shows the results of evaluating the water resistance and light resistance of these recording papers.

Example 5 80 parts of LBKP of 370 m1 CSF, water density 4
Pulp slurry consisting of 20 parts of NBKP of 001nlC8F, 15 parts of talc, and Tubujil LP in white carbon.
, manufactured by Nippon Silica Co., Ltd.), 1 part of cationic starch,
A base paper with a basis weight of 65 F//m' is made by adding it to 0.01 part of polymeric acrylamide using a Fourdrinier paper machine in a conventional manner, and at the time of making the paper, a size press machine is used to add 2% polyvinyl alcohol and 1,000-ionic colloidal. Size press liquid consisting of 4% silica (Snowtex-AK1 manufactured by Nissan Chemical Co., Ltd.) was heated to 80 fF.
/- to form the recording paper of Example 5.

Table 1 shows the results of evaluating the water resistance and light resistance of this recording paper.

Comparative Example 2 A base paper made in the same manner as in Example 5 was heated to 80fF/2% polyvinyl alcohol solution using a size press during papermaking.
- The recording paper of Comparative Example 2 was prepared by adhesion.

Table 1 shows the results of evaluating the water resistance and light resistance of this recording paper.

Comparative Example 3゜A size press fft80i/rrl consisting of 2% polyvinyl alcohol and 1% cationic resin (Borifix-601, Showa Kobunshi) was applied to a base paper made in the same manner as in Example 5 and then put into a cosize press machine during papermaking. The recording paper of Comparative Example 3 was obtained by adhering the film. Table 1 shows the results of evaluating the water resistance and light resistance of this recording paper.

Table 1 Axis) Effect of the Invention As is clear from Table 1, in Examples 1 to 5 containing cationic colloidal silica, the water resistance was significantly improved compared to Comparative Example L2 without additives, and the light resistance Almost no decrease was observed. In Comparative Example 3, the water resistance was good, but the light resistance was significantly reduced, and both properties were not compatible. From this, it is clear that Examples 1 to 5 containing cationic colloidal silica according to the present invention are recording papers that have improved water resistance and are also extremely excellent in light resistance.

Claims (1)

[Claims] An inkjet recording paper comprising a fibrous substance and a filler, characterized in that the recording paper contains cationic corodal silica.