JP2002362009A - Ink jet recording sheet and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording sheet at low cost, which is excellent in monochrome bleeding, mixed color bleeding and water resistance in an ink jet recording sheet, in which recording is performed with ink, and its manufacturing method. SOLUTION: In this ink jet recording sheet, in which an ink accepting layer including a pigment mainly made of silica and calcined clay, a binder and a dye fixing agent is provided on a support mainly made of cellulose fibers, the pigment is mainly made of synthetic amorphous silica and the calcined clay under the weight ratio between the synthetic amorphous silica and the calcined clay lies within the range of 80/20 to 40/60.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet for recording using ink.
More specifically, the present invention relates to providing an ink jet recording sheet excellent in monochrome bleeding, mixed color bleeding, and water resistance at low cost.

[0002]

2. Description of the Related Art The ink jet recording system is used in various printers which generate little noise, do not require a process such as development and fixing, and can easily perform full color recording, and have been rapidly spreading in recent years. In particular, due to the advantages that a color image is formed by a computer, that the recording apparatus can be made relatively small, that the maintenance of the apparatus is easy, and that driving noise and recording noise are very low. In recent years, it has been used as a recording method for facsimile and various printers.

[0003] More recently, with the demand for higher speed and higher definition of the ink jet recording system, the performance of the ink jet recording apparatus has been improved and the use thereof has been expanded. .

First, as an ink jet recording sheet, the print density of an image is high, the color tone is bright and clear, the ink absorbs quickly, the ink does not flow or bleed even when the print images overlap, It is required to have excellent image clarity such that the diffusion in the vertical and horizontal directions is not unnecessarily large and the periphery is smooth.

[0005] Further, regarding the storage stability, it is required that the printed image has excellent water resistance so that the ink does not flow out even under high humidity conditions or when the printed image portion is damaged by water. .

In order to satisfy such demands, a so-called coated paper type is provided with an ink receiving layer mainly composed of a pigment such as silica on a paper as a support to improve image clarity and the like. I have. Further, by containing a cationic polymer dye fixing agent in the ink receiving layer, the water resistance of the printed image is improved.

However, the components constituting the ink receiving layer are generally expensive. In order to reduce costs, if the coating amount of the ink receiving layer is reduced, ink bleeding,
Problems such as strike-through of ink and reduction in water resistance occur.

[0008] Regarding ink bleeding, it is considered that, by reducing the coating amount, the ink absorption capacity becomes insufficient, and the ink overflows without being absorbed by the ink receiving layer. In particular, if the spread of the dots in the horizontal direction is large, the bleeding of the ink is inferior.

[0009] The strike-through of the ink is a phenomenon in which the absorption of the ink is not sufficient only by the absorbency of the ink receiving layer, and the penetration of the ink into the base paper as the support becomes excessive. In a broad sense, the strikethrough of the ink includes the strikethrough of the ink. When ink penetrates into the base paper, a phenomenon called cockling (a state where the recording sheet is wavy) occurs.

The decrease in water resistance is considered to be due to a shortage of a cationic component for fixing an anionic ink due to a small amount of the cationic polymer dye fixing agent contained in the ink receiving layer. . When the coating amount is reduced, the amount of the cationic polymer dye fixing agent contained in the coating layer is relatively reduced, and when the printed image portion is affected by water, a phenomenon that ink flows out is caused. As with ink bleeding, reducing the amount of coating reduces the absorption capacity of the ink, and if it is affected by water, the ink cannot be absorbed by the ink receiving layer and the overflow of the ink is promoted. It is thought to be.

[0011]

SUMMARY OF THE INVENTION Therefore, the present invention provides an ink jet recording sheet which is excellent in monochrome bleeding, mixed color bleeding and water resistance, and a method for producing the same, at low cost. Aim.

[0012]

According to the first aspect of the present invention, an ink receiving layer containing a pigment and a binder mainly composed of silica and calcined clay and a dye fixing agent is provided on a support mainly composed of cellulose fibers. In the ink jet recording sheet, the pigment is mainly composed of synthetic amorphous silica and calcined clay, and the weight ratio of the synthetic amorphous silica to calcined clay is in the range of 80/20 to 40/60. .

The invention according to claim 2 is the invention wherein the weight ratio of the pigment to the binder is 100/100 to 100/15, and the pigment contains synthetic amorphous silica having an average aggregated particle diameter of 1 to 20 μm; An ink jet recording sheet comprising a calcined clay having a specific surface area of 15 to 25 m ² / g, wherein the binder is polyvinyl alcohol and ethylene vinyl acetate.

According to the third aspect of the present invention, JIS P-8
3. The ink jet recording sheet according to claim 1, wherein the static friction coefficient measured at 147 is 0.8 to 0.4 and the dynamic friction coefficient is 0.7 to 0.3.

According to a fourth aspect of the present invention, there is provided the ink jet recording sheet according to the first, second or third aspect, wherein the coating amount of the ink receiving layer is 3 to 9 g / m ² .

The method for producing an ink jet recording sheet according to the present invention comprises the steps of: a synthetic amorphous silica having an average aggregated particle diameter of 1 to 20 μm; a pigment mainly composed of calcined clay having a specific surface area of 15 to 25 m ² / g; A coating solution containing a binder composed of an ethylene vinyl acetate resin and a dye fixing agent is applied by a rod bar coating method onto a support mainly composed of cellulose fibers so that the coating amount of the ink receiving layer is 3 to 9 g / m ² . It is to be coated so that it becomes.

Further, the method of manufacturing an ink jet recording sheet according to the present invention has a static friction coefficient of 0.8 to 0.4 and a kinetic friction coefficient of 0.7 to 0.4 measured according to JIS P-8147.
In order to obtain 3, the ink receiving layer contains a lubricant or a curl liquid containing a lubricant is applied to the back surface of the support.

The pigment used in the present invention is desirably used as a mixture of synthetic amorphous silica and calcined clay.
A system using only synthetic amorphous silica has good ink absorbency, and is excellent in monochrome bleeding, mixed color bleeding, and clarity of a printed image, but has a problem that the cost is higher than other pigments. In addition, synthetic amorphous silica has a problem that it is difficult to disperse it at a high concentration and the production efficiency in the coating and drying steps is poor.

Therefore, the above-mentioned problems are improved by using a calcined clay which has a great cost advantage as compared with synthetic amorphous silica. When a calcined clay is mixed with synthetic amorphous silica and used, high-concentration dispersion can be performed, so that the efficiency of the drying step can be increased. When the weight ratio of the calcined clay is increased, there is a cost advantage, but the ink absorbency is not so good, and there is a tendency that monochrome bleeding, mixed color bleeding, and clarity of a printed image are poor.

The weight ratio of the synthetic amorphous silica to the calcined clay is preferably in the range of 80/20 to 40/60, more preferably 70/30 to 50/50. When the weight ratio of the calcined clay is lower than 20, there is a problem that high concentration dispersion cannot be performed and the production efficiency is deteriorated.
If the amount is larger, the ink absorbency is poor, and there is a problem in printing quality such as monochrome bleeding, mixed color bleeding, and clarity of a printed image.

The weight ratio between the pigment and the binder is 100/1.
00/100/15 is preferable, and 100/100 is more preferable.
60 to 100/20. When the weight ratio of the binder is 1
If it exceeds 00, the ink absorbency becomes poor, and the monochrome blur and the mixed color blur tend to be inferior. This is because if the amount of the binder component is more than necessary, the pores of the pigment particles are covered, and the ink absorbability is impaired. When the weight ratio of the binder is less than 15, the acting force for fixing the pigment particles to the paper surface is weakened, which causes problems such as powder dropping of the coating layer.

The pigment preferably contains a synthetic amorphous silica having an average agglomerated particle diameter of 1 to 20 μm, and more preferably 3 to 20 μm.
15 μm is more practical. According to a further preferred embodiment of the present invention, it comprises a calcined clay having a specific surface area of 15 to 20 m ² / g, wherein the binder is polyvinyl alcohol and ethylene vinyl acetate.

The friction coefficient of the ink jet recording sheet is as follows:
The coefficient of static friction is 0.8 to 0.4, more preferably 0.7 to 0.4.
0.5, and the dynamic friction coefficient is preferably in the range of 0.7 to 0.3, more preferably 0.6 to 0.4. When printing a large number of sheets in practice, paper transportability is important. If the coefficient of friction of the paper is too high, two or more sheets will be multi-fed, and if the coefficient of friction of the paper is too low, the paper will slip too much and the paper alignment will be poor, making it difficult to handle.

As a method of adjusting the friction coefficient, a lubricant may be contained in the ink receiving layer to such an extent that the print quality is not reduced. However, in consideration of the influence on the print quality and the like, it is preferable to apply a curl liquid containing a lubricant on the back surface. As the lubricant, various known lubricants such as polyethylene wax, paraffin wax, calcium stearate, and zinc stearate can be used.

According to a preferred embodiment of the present invention, the coating amount of the ink receiving layer is 3 to 9 g / m ^2, more preferably 5 to 7 g / m ^2.
g / m ² . As a coating method, a rod bar coating method is preferable. The greater the coating amount of the ink receiving layer, the more excellent the ink absorption, the less the bleeding of the ink, and the better the sharpness of the printed image. However, the components constituting the ink receiving layer are relatively expensive, and if the coating amount is increased, processing costs in the liquid preparation step, the coating step, and the drying step are required, which is not efficient. In the present invention, the ink receiving layer is preferably a single layer. Compared to those coated with a single layer, those coated with multiple layers have poor ink absorbency,
There is a problem that color mixing blur occurs.

The ink-receiving layer is formed by coating a coating solution prepared by dispersing the components for forming the ink-receiving layer in a suitable solvent on a support by a rod bar coating method. It is desirable to do it. Advantages include good productivity in the coating and drying steps, and easy maintenance of the apparatus.

The paper, which is a support mainly composed of cellulose fibers, is not particularly limited. Examples of the internal sizing agent and the external sizing agent to be used include a neutral rosin sizing agent or AKD, ASA, and reinforced sizing agent. Various known materials such as a rosin sizing agent can be used. The method of internally and externally adding the sizing agent to the paper may be appropriately selected depending on the type of the sizing agent.

As the paper machine, any of a round net type and a long net type can be used. The surface sizing agent is processed by size press,
A gate roll, a metering size press, an air knife coater, a rod coater, a blade coater, and the like are all possible.

A filler retention improver, a coloring pigment, a dye or a fluorescent dye for improving the whiteness of appearance can be used. Examples of the retention aid include polyacrylamide, polyethyleneimine, and cationized starch. Further, if necessary, an antifoaming agent can be added in order to prevent foaming of the raw material in the papermaking process.

Other components may be added to the ink receiving layer according to the present invention in order to enhance the properties of the ink jet recording sheet. For example, melamine formaldehyde resin, urea formaldehyde resin, acrylamide resin, glyoxal, zirconium ammonium carbonate, secondary ammonium compound, tertiary ammonium compound, A dye fixing agent such as a quaternary ammonium compound may be added. In addition, in consideration of the productivity and storage stability of the inkjet recording sheet, a dispersant, a fluorescent dye,
A pH adjuster, an antifoaming agent, a surfactant, a wetting agent, a water retention agent, a preservative, and the like may be added.

In particular, from the viewpoint of improving the water resistance of the ink and the fixing of the ink, a cationic polymer dye fixing agent such as a secondary ammonium compound, a tertiary ammonium compound, or a quaternary ammonium compound is added to the ink receiving layer. It is preferred to include.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to examples. Of course, the present invention is not limited to these. Parts and% in the examples are parts by weight and% by weight, respectively, unless otherwise specified.

Example 1 [Support] Calcium carbonate (Tamapearl TP-121: manufactured by Okutama Kogyo Co., Ltd.) based on 100% of absolutely dry pulp in a pulp slurry composed of hardwood bleached kraft pulp L-BKP
Paper was made with a composition of 5%, cationized starch (Kate 308: NSC Japan) 0.8%, and neutral rosin sizing agent (NT-85: Arakawa Chemical Co., Ltd.) 0.4%. ²
Base paper was made. [Ink receiving layer] 60 parts of silica (Mizukasil P-78A: manufactured by Mizusawa Chemical Industry Co., Ltd.) having an average aggregated particle diameter of 3.3 μm,
Fired clay having a specific surface area of 18 m ² / g (Ansilex 9
3: 40 parts of Engelhart Co., Ltd., 10 parts of polyvinyl alcohol (PVA-235: Kuraray Co., Ltd.), 20 parts of ethylene vinyl acetate resin (Polysol EVA AD-6: manufactured by Showa Polymer Co., Ltd.), fixing cationic polymer dye 20 parts of an agent (Smileds Resin 1001: manufactured by Sumitomo Chemical Co., Ltd.) and water were mixed to obtain a coating solution having a solid content of 26%. The coating liquid of the ink receiving layer was coated on a support using a rod bar coater at a line speed of 300 m / min so as to have an absolute dry coating amount of 6 g / m ² (coating frequency: 1). An ink jet recording sheet was obtained. At this time, a curl liquid containing polyethylene wax (SN Coat 289: manufactured by San Nopco Co., Ltd.) was prepared and adjusted to have a static friction coefficient of 0.62 and a dynamic friction coefficient of 0.52.

Example 2 In Example 1, 80 parts of silica and 20 parts of calcined clay were used.
An ink jet recording sheet was obtained in the same manner as in Example 1 except that the coating liquid having a solid content of 22% and the line speed were 280 m / min.

Example 3 In Example 1, 40 parts of silica and 60 parts of calcined clay were used.
An ink jet recording sheet was obtained in the same manner as in Example 1, except that the coating liquid was 28% solids and the line speed was 340 m / min.

Example 4 An ink jet recording sheet was obtained in the same manner as in Example 1 except that 30 parts of polyvinyl alcohol and 60 parts of ethylene vinyl acetate resin were used.

Example 5 An ink jet recording sheet was obtained in the same manner as in Example 1, except that 20 parts of polyvinyl alcohol and 40 parts of ethylene vinyl acetate resin were used.

Example 6 An ink jet recording sheet was obtained in the same manner as in Example 1, except that 15 parts of polyvinyl alcohol and 30 parts of ethylene vinyl acetate resin were used.

Example 7 An ink jet recording sheet was obtained in the same manner as in Example 1, except that 5 parts of polyvinyl alcohol and 10 parts of ethylene vinyl acetate resin were used.

Example 8 An ink jet recording sheet was obtained in the same manner as in Example 1 except that 15 parts of polyvinyl alcohol and 15 parts of ethylene vinyl acetate resin were used.

Example 9 An ink jet recording sheet was obtained in the same manner as in Example 1, except that 20 parts of polyvinyl alcohol and 10 parts of ethylene vinyl acetate resin were used.

Example 10 An ink jet recording sheet was obtained in the same manner as in Example 1, except that the coating liquid for the ink receiving layer was 4 g / m ^{2 in} absolute dry coating amount.

Example 11 An ink jet recording sheet was obtained in the same manner as in Example 1, except that the coating liquid for the ink receiving layer was 8 g / m ² in a dry amount.

Comparative Example 1 In Example 1, 100 parts of silica and 0 parts of calcined clay were used.
An ink jet recording sheet was obtained in the same manner as in Example 1 except that the coating liquid was 18% solids and the line speed was 240 m / min (the number of coatings was two).

Comparative Example 2 In Example 1, 20 parts of silica and 80 parts of calcined clay were used.
An ink jet recording sheet was obtained in the same manner as in Example 1 except that the coating liquid was 28% solids and the line speed was 340 m / min.

Comparative Example 3 An ink jet recording sheet was obtained in the same manner as in Example 1 except that 40 parts of polyvinyl alcohol and 80 parts of ethylene vinyl acetate resin were used.

Comparative Example 4 An ink jet recording sheet was obtained in the same manner as in Example 1, except that 2.5 parts of polyvinyl alcohol and 5 parts of ethylene vinyl acetate resin were used.

Comparative Example 5 An ink jet recording sheet was obtained in the same manner as in Example 1, except that the coating amount of the ink receiving layer was changed to 2 g / m ² on a dry basis.

Comparative Example 6 Ink jet recording was carried out in the same manner as in Example 1, except that the coating amount of the ink receiving layer was 12 g / m ² (3 coating times). I got a sheet.

Comparative Example 7 An ink jet recording sheet was obtained in the same manner as in Example 1, except that the calcined clay was calcium carbonate (Tamapearl TP-121: manufactured by Okutama Industry Co., Ltd.).

Comparative Example 8 In Example 1, a curl liquid containing no polyethylene wax was used, and the static friction coefficient was 0.92 and the dynamic friction coefficient was 0.88.
An ink jet recording sheet was obtained in the same manner as in Example 1, except that

With respect to the ink jet recording sheet thus obtained, the clearness of printed images, water resistance, ink strike-through, and cockling were evaluated by the following methods, and the results are shown in Table 1. Ink jet printers are Epson's MJ-500 machine and Canon's BJC-21.
It was printed with a 0J machine.

"Monochrome bleeding": Monochrome bleeding was visually evaluated by printing with an MJ-500 machine. ：: Characters can be read very clearly, with almost no bleeding in the monochrome printing area. ：: Bleeding of the monochrome printing portion is small, and characters can be read clearly. Δ: Bleeding of the monochrome print portion was slight, and characters were difficult to read a little. ×: Bleeding of the monochrome printing area makes it difficult to read characters.

"Mixed-color bleeding": Bleeding with a BJC-210J machine was visually evaluated for mixed-color bleeding. A: Characters can be read very clearly with little bleeding in the mixed color printing area. ：: The bleeding of the mixed color printing portion is small, and the characters can be clearly read. Δ: Bleeding of the mixed color printing portion was slight, and characters were difficult to read a little. X: Bleeding of the mixed-color printing portion, making it difficult to read characters.

"Water resistance": A solid printed portion was immersed in water for 5 seconds, wiped off with a filter paper, and evaluated for ink flow. A: There is no outflow of ink and the water resistance is very good. ：: Outflow of ink is inconspicuous and water resistance is good. C: Water resistance is slightly poor, for example, ink flows out in secondary colors. ×: In general, outflow of ink occurs and water resistance is extremely poor.

"Strength": The coated surface was rubbed with a finger to evaluate powder loss. ◎: Very good, with no powder falling off the coated surface and not sticking to fingers. ：: Good powder with little powder falling on the coated surface and not much adhered to the finger. Δ: Powder was slightly removed from the coated surface and slightly adhered to the finger. ×: Powder was removed from the coated surface and also adhered to the finger.

"Productivity": It was evaluated whether the coating speed was high, the number of coating times was as small as possible, and the productivity (operability) was good. A: The line speed can be very high, and the productivity is very good. ：: The line speed can be increased, and one of the productivity is good. Δ: The line speed could not be too high, and the productivity was not very good. X: The line speed could not be increased, and the productivity was not very good.

"Conveyance": It was evaluated whether the recording sheet was conveyed smoothly without double feed or the like. ：: There is almost no double feed (double feed 0 to 5 per 500 sheets)
), Transported very smoothly. ：: Although there is a little double feed (double feed 6 to 20 per 500 sheets)
Sheets), and are transported smoothly. Δ: There is some double feed (double feed 21 to 50 per 500 sheets)
Sheets), it is not transported very smoothly. ×: Many double feeds (50 or more double feeds per 500 sheets) are not carried smoothly.

[0059]

[Table 1]

[0060]

[Table 2]

[0061]

As is clear from the results shown in Tables 1 and 2, the ink jet recording sheet obtained according to the embodiment of the present invention provides an ink jet recording sheet excellent in monochrome bleeding, mixed color bleeding and water resistance at low cost. can do.

The present invention uses a mixture of the synthetic amorphous silica and calcined clay at the above-mentioned weight ratio to provide good ink absorbency, excellent monochrome and mixed color bleeding, excellent clarity of printed images, and high density. Since the dispersion can be performed, the efficiency of the drying step can be increased.

According to the present invention, by specifying the friction coefficient of the ink jet recording sheet within the above range, the double feeding trouble is solved, the paper transportability is good, and the paper alignment is good.

In the method for producing an ink jet recording sheet of the present invention, in forming the ink receiving layer, a coating liquid of a component for forming the ink receiving layer is coated on a support by a rod bar coating method. Therefore, the productivity in the coating step and the drying step is good, and the maintenance of the apparatus is easy.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2C056 EA05 EA13 FC06 2H086 BA02 BA15 BA21 BA31 BA33 BA34 BA41 BA45 BA48 4D075 BB92Z BB99Z CA06 CA35 CA38 CA47 DA04 DB18 DC27 EA07 EA10 EB13 EB19 EB22 EC53 EC53 EC53 EC53

Claims (6)

[Claims] 1. An ink jet recording sheet comprising a support mainly composed of cellulose fibers and an ink receiving layer containing a pigment, a binder mainly composed of silica and calcined clay, and a dye fixing agent mainly composed of silica and calcined clay. An ink jet recording sheet mainly comprising porous silica and calcined clay, and having a weight ratio of synthetic amorphous silica to calcined clay of 80/20 to 40/60. 2. A pigment / binder weight ratio of 100 /
100 to 100/15, wherein the pigment comprises a synthetic amorphous silica having an average aggregated particle diameter of 1 to 20 μm and a calcined clay having a specific surface area of 15 to 25 m ² / g, and the binder is polyvinyl alcohol 2. The ink jet recording sheet according to claim 1, wherein the recording sheet is ethylene vinyl acetate. 3. The static friction coefficient measured according to JIS P-8147 is 0.8 to 0.4 and the dynamic friction coefficient is 0.7 to 0.3.
The ink jet recording sheet according to claim 1, wherein: 4. The coating amount of the ink receiving layer is 3 to 9 g /
ink-jet recording sheet according to claim 1, 2 or 3, characterized in that a m ^2. 5. A pigment composed mainly of calcined clay having an average agglomerated particle diameter of 1 to 20 μm, a calcined clay having a specific surface area of 15 to 25 m ² / g, a binder composed of polyvinyl alcohol and an ethylene vinyl acetate resin, and a dye. A coating solution containing a fixing agent is applied by a rod bar coating method on a support mainly composed of cellulose fibers so that the coating amount of the ink receiving layer is 3 to 9 g / m ^2. Of producing an inkjet recording sheet. 6. The method for producing an ink jet recording sheet according to claim 5, wherein the static friction coefficient measured according to JIS P-8147 is 0.8 to 0.4 and the dynamic friction coefficient is 0.7.
6. The ink jet recording sheet according to claim 5, wherein a lubricant is contained in the ink receiving layer so as to be 0.3 or a curl liquid containing the lubricant is applied to the back surface of the support. Manufacturing method.