JPH06247036A - Ink-jet recording paper - Google Patents

Abstract

PURPOSE:To provide ink-jet recording paper which is superior in uniformity in density and coating strength. CONSTITUTION:Ink-jet recording paper possesses a support body, a lower layer which is formed on one surface of this substrate and consists mainly of an organic boron compound polymer, water-soluble resin which is laminated on the lower layer and possesses noncrystalline fine powder silica and a hydroxyl group capable of reacting upon the organic boron compound and an ink receptive coating layer containing a cationic polymer as a main component.

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 using a water-based ink for use in printers, copying machines, etc. The present invention relates to an improved ink jet recording sheet having excellent properties such as high absorption speed and ink absorption capacity, excellent color development, vivid, sharp images and printing.

[0002]

2. Description of the Related Art The performance of ink jet printers that use water-based ink, especially the printing speed, resolution, and gradation, has been improved, so that high-speed absorption, high absorption capacity, and high density In addition to the improvement of printing and image quality, more advanced properties such as water resistance of printed matter, strong base material and ink-receptive coating layer, and water resistance have been required.

For example, Japanese Patent Application Laid-Open No. 55-51583 discloses that a coating layer comprising non-colloidal silica and a polymer binder is provided in order to enable high density printing, and Japanese Patent Publication No. JP-A-52786 discloses a method of using a silyl group-containing modified polyvinyl alcohol for an inkjet recording medium in order to improve coating film strength and water resistance while having ink absorbability in printing with an aqueous ink. However, in all of these, the strength is improved, but the ink absorbency is reduced.

Further, Japanese Patent Application Laid-Open No. 56-84992 discloses a method using a polycationic polymer electrolyte. In this case, the water resistance of the printed matter is improved, but the strength is not sufficiently improved. In addition, JP-A-4-2231
In JP-A-90, coating strength is improved by applying borax or boric acid on the surface of a base paper of a release paper, and further providing a recording layer containing silica and polyvinyl alcohol as main components,
Although it is described that high-resolution ink jet recording is possible, when borax and boric acid are applied to the base paper, they are easily absorbed by the base paper, so the application effect is not sufficiently exerted, and borax and boric acid are not easily applied. Further improvement has been demanded for applications requiring processing suitability such as having no powder drop and for use in environments exposed to high humidity and water droplets after printing.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides an ink jet printer using a liquid ink, which has good print density and print quality, and is capable of bending the ink receptive coating layer.
The present invention is intended to provide an inkjet recording sheet which is free from powder drop during cutting and has good processability.

[0006]

As a result of various investigations by the present inventors, a support and a lower layer formed on one surface of the support and containing an organic boron compound polymer as a main component, By being laminated on this lower layer and having an amorphous fine powder silica, an ink receptive coating layer containing a water-soluble resin having a hydroxyl group capable of reacting with the organic boron compound polymer and a cationic polymer as main components, The present invention has been completed by finding that the drawbacks of the prior art as described above can be solved.

The recording paper of the present invention has good print density and print quality, excellent surface strength of the ink-receptive coating layer, good processability, and water and moisture resistance of images and substrates. It is an excellent inkjet recording paper.

The support used for the recording paper of the present invention is
It can be appropriately selected and used from known materials. For example, not only paper base materials mainly composed of natural pulp such as high-quality paper, medium-quality paper and recycled paper, but inorganic fine pigments of 8 to 6 are used.
A thermoplastic resin film containing 5%, comprising a base material layer,
In addition to the paper-like layer, it is composed of a multilayer structure including a surface layer depending on the application.
It is used by selecting from a wide range of materials such as semi-transparent trace paper type synthetic paper. Here, as the thermoplastic resin, polyolefin resin, for example, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer as a main component, in addition, polystyrene, acrylic ester copolymer, etc. These thermoplastic resins can be mixed and used. The ink jet recording paper in the present invention means all ink jet recording sheets having the above-mentioned paper base material and synthetic paper as a support.

Examples of the inorganic fine powder pigment that can be blended with the thermoplastic resin include calcium carbonate having an average particle size of 20 μm or less, calcined clay, diatomaceous earth, talc, silica, etc. in the base material layer and the paper-like layer. However, examples of the surface layer include calcium carbonate, titanium oxide, barium sulfate and the like. The thickness of the sheet-like support used for the recording paper of the present invention is preferably 10 to 200 μm, and the basis weight is preferably 10 to ²⁰⁰ g / m ² , and those having good surface smoothness are preferred.

Further, the sheet-like support of the present invention includes, in addition to the above-mentioned biaxially stretched multi-layered polyolefin sheet containing an inorganic fine powder pigment, a synthetic resin such as a polyester film or a polyolefin film, or a natural resin. It is also possible to use a transparent, semi-transparent or opaque film of resin or the like as the substrate.

The organic boron compound polymer used in the recording paper of the present invention is represented by the following chemical formula 1.

[0012]

[Chemical 1]

[However, W, X, Y and Z are each H
Or R-CO- group (however, R is a total carbon number of 11 to 2)
1 hydrocarbon group), and at least one of W, X, Y, and Z is an R—CO— group, and p is 10 to 10
It is 1000. ]

The boron-based polymer compound of Chemical formula 1 is
It can be produced by the method described in JP-A-53331.

In the lower layer of the recording paper of the present invention,
In addition to the boron-based polymer compound, a water-soluble adhesive such as starch or polyvinyl alcohol, calcium carbonate, etc., if necessary, as long as the function of the boron-based polymer compound is not impaired.
A pigment such as clay can also be added. The lower layer of the recording paper of the present invention has a coating amount of 0.1 to 2 g on one surface of the support.
It is preferable to provide it at a ratio of / m ² . If the coating amount of the lower layer is less than 0.1 g / m ² , the effect is insufficient and the strength of the coating film is insufficient. On the other hand, if the coating amount exceeds ² g / m ² , not only the effect is saturated, but also the ink absorbency is insufficient, causing bleeding, which is not preferable.

As described above, the ink-receptive coating layer in the recording paper of the present invention is mainly composed of amorphous finely divided silica, a water-soluble adhesive and a cationic polymer. The amorphous fine powder silica used is desirably used for inkjet paper to give a clear image, and such a pigment has a high oil absorption and a high specific surface area.
The secondary particles having a particle size of 1 to 6 μ are most excellent. Finely divided silica accounts for 50 to 8 of the total solid content in the ink receptive coating layer.
It is suitable to use 0% by weight. If the amount of finely divided silica is less than 50% by weight, the absorption capacity of the ink is reduced, ink bleeding occurs, and the dot diameter increases, which is not preferable. Also,
When the amount is more than 80% by weight, the image quality is good, but the coating film strength is lowered, which causes a problem in practical use.

In addition, other white pigments can be used in combination depending on the purpose of use of the paper and the required performance of the printer. For example, zeolite, calcium carbonate, diatomaceous earth, kaolin, calcined clay, talc, aluminum hydroxide, organic pigments. Pigments generally used for paper coating such as (plastic pigment) can be used. Further, since the above pigment is used as a paint, it is preferable to add an ordinary dispersant in order to uniformly disperse the pigment in water, and for example, sodium polyacrylate, phosphate, surfactant and the like can be used.

The water-soluble resin used in the ink-receptive coating layer has a degree of polymerization of 300 to 3000 and a degree of saponification of 75 to 1
Vinyl alcohol adhesive modified with 00% polyvinyl alcohol, silanol group, vinyl alcohol copolymer containing acetoacetyl group, tertiary aminoalkyl group, quaternary ammonium group, iminoalkyl group, aminoalkyl group, etc. Water-soluble resins such as agents are mentioned. In addition, as the water-soluble adhesive having a hydroxyl group as a functional group that reacts with the organic boron compound polymer represented by Chemical formula 1,
For example, starch derivatives such as oxidized starch, esterified, etherified, and grafted starch, cellulose derivatives, and water-soluble acrylic copolymers can be used. Furthermore, a water-dispersible adhesive such as a styrene-butadiene resin or an acrylic copolymer can be appropriately selected and used as necessary.

The amount of the above water-based adhesive compounded is preferably 10 to 30% by weight of the total solid content of the ink-receptive coating layer, and if it is 30% by weight or more, the resolution of the image and the ink absorption speed are lowered. However, there is a problem that the ink dryness is lowered and the printing clarity is lowered. On the other hand, if it is 10% by weight or less, sufficient strength of the ink receptive coating layer cannot be obtained, which is not preferable.

In the recording paper of the present invention, it is desirable to add a cationic polymer in order to make the image waterproof.
As the cationic polymer, an acrylic or methacrylic acid ester copolymer containing a quaternary ammonium salt of polyethyleneimine as a copolymerizable monomer is suitable. The amount of these cationic polymers blended is 2 to 20 of the total solid content of the ink receptive coating layer.
It is preferable to exist in the range of wt%, and when the amount is 2% by weight or less, a sufficient effect cannot be obtained, and when the amount is 20% by weight or more, the effect is saturated, and further improvement cannot be obtained. Is decreased, which is not preferable. If necessary, a water-soluble crosslinking agent such as an aldehyde type or glycidyl type may be added.

The ink-receptive coating layer of the recording paper of the present invention is preferably ² to 20 g / m ² in view of the ink absorption capacity, absorption rate, image density, resolution and the like. When the coating amount is less than 2 g / m ² , the ink absorption capacity of the heavy color portion in color printing becomes insufficient, which causes blurring. Further, if it exceeds 20 g / m ² , the effect is saturated and the cost is increased, which is not preferable.

The ink-receptive coating layer of the recording paper of the present invention is prepared by uniformly dispersing the above-mentioned constituents in water to prepare a coating solution, which is prepared, for example, by a bar coater, a blade coater, an air knife coater, It is coated on at least one surface of the support by a coating method such as a gravure coater. After coating, if necessary, super calendering may be performed for surface smoothing.

[0023]

The present invention will be described in more detail with reference to the following examples, but of course the present invention is not limited thereto. In the following,% means% by weight of solid content. Example 1 A high-quality paper having a basis weight of 70 g / m ² was coated with an organic boron compound polymer (Hiboron DDGB-90, average molecular weight of 10,000).
0, boron content 6.2%: 3% aqueous solution of Boron International Co., Ltd. was size-pressed to provide a lower layer with a coating amount of 0.6 g / m ² . Furthermore, paint-1 with a concentration of 1
Prepared to 2% by weight, and the solid content is 4 with an air knife coater.
An ink-receptive coating layer was provided by coating at a rate of g / m ² and drying, and treated with a super calendar to prepare an inkjet recording paper.

The paint -1 Ingredient Weight amorphous fine silica powder (FINESIL: Tokuyama Soda Co., Ltd.) 70% polyvinyl alcohol (PVA-105: manufactured by Kuraray) 26% polyethyleneimine quaternary ammonium salt (waterproofing agent) 3% Sodium polyacrylate (dispersant: Toagosei) 1%

Example 2 An organic boron compound polymer (Hyboron DDGB-90, average molecular weight of 10,000) was applied to a wood free paper having a basis weight of 70 g / m ^2.
0, boron content 6.2%: 8% aqueous solution of Boron International Co., Ltd. was size-pressed to provide a lower layer with a coating amount of 2.5 g / m ² . Furthermore, paint-2 with a concentration of 1
Prepared to 2% by weight, and the solid content is 4 with an air knife coater.
An ink-receptive coating layer was provided by coating at a rate of g / m ² and drying, and treated with a super calendar to prepare an inkjet recording paper.

[0026] Paint -2 Ingredient Weight amorphous fine silica powder (FINESIL: Tokuyama Soda Co., Ltd.) 50% diatomaceous earth 15% modified starch (Peter Court C-8: Nippon Starch Chemical Co., Ltd.) 25% quaternary ammonium salt Containing acrylic copolymer emulsion 9% Sodium polyacrylate (dispersant: Toagosei) 1%

Example 3 A high-quality paper having a basis weight of 70 g / m ² was coated with 50% by weight of an organoboron compound polymer (Hiboron DDGB-90, average molecular weight 1).
50,000, boron content 6.2%: manufactured by Boron International Co., Ltd., oxidized starch 50% by weight (Ace A:
An 8% aqueous solution of Oji Corn Starch) was size-pressed to provide a lower layer with a coating amount of 1 g / m ² . Furthermore, paint-
2 was prepared to have a concentration of 12% by weight, coated with an air knife coater at a solid content of 4 g / m ² and dried to provide an ink receptive coating layer, and treated with a super calendar to prepare an inkjet recording paper. .

The paint -3 Ingredient Weight amorphous fine silica powder (Mizukasil: Mizusawa Chemical Industries, Ltd.) 68% silanated polyvinyl alcohol (R-1130: manufactured by Kuraray) 28% polyethyleneimine quaternary ammonium salt 3% polyacrylic acid Soda (dispersant: manufactured by Toagosei) 1%

Comparative Example 1 Paint-1 was prepared in a concentration of 12% by weight on a high-quality paper having a basis weight of 70 g / m ² , and the solid content was 4 g / m with an air knife coater.
Coating at a ratio of ² and drying to provide an ink receptive coating layer,
An inkjet recording paper was prepared by processing with a super calendar.

Comparative Example 2 A 5% aqueous solution of oxidized starch (Oji Ace A: made by Oji Corn Starch) was size-pressed on a high-quality paper having a basis weight of 70 g / m ² , and the lower layer was provided with a coating amount of 2 g / m ² . Furthermore, paint-2 was prepared in a concentration of 12% by weight, coated with an air knife coater at a solid content of 4 g / m ² , and dried to form an ink-receptive coating layer, which was then treated with a super calendar for inkjet recording. I made a paper.

Table 1 shows the evaluation results of these recording materials. The recording characteristics of the inkjet paper were evaluated by a color density using an inkjet printer (BJC-820J manufactured by Canon Inc.). The color density was measured on the printed matter with a Macbeth densitometer. The uniformity of print density was visually evaluated for the uniformity of solid print portions of cyan, magenta, and yellow. Black-, blue-, red-, and green-printing was carried out on the heavy-color printed blemishes, and the bleeding at the adjacent portions was visually evaluated. The strength of the ink-receptive coating layer was sensory evaluated by sticking a commercially available cellophane tape on the surface and observing the degree of peeling of the coating layer when peeling the tape. The evaluation results are indicated by ◯ for excellent performance, Δ for general quality, and x for defects having problems in use.

[0032]

[Table 1] Table 1 Inkjet recording paper quality evaluation ───────────────────────────────── Color density Density Uniformity Color printing smear Coating strength ───────────────────────────────── Example 1 1.42 △ 〇 〇 21 .40 〇 〇 〇 3 1.41 〇 〇 〇 ────────────────────────────────── Comparative Example 1 1. 38 × × ○ 2 1.42 ○ × × ──────────────────────────────────

As is clear from Table 1, the recording paper of the present invention is provided with a lower layer mainly composed of an organic boron compound polymer,
Further, by providing an amorphous fine powder silica, a water-soluble adhesive having a hydroxyl group capable of reacting with the organic boron compound polymer, and a coating layer containing a cationic polymer as a main component,
A recording paper which has good print density and print quality of an image by ink jet recording, excellent surface strength of the ink-receptive coating layer and good processability, and which satisfies the water resistance and humidity resistance of the image and the substrate. (Example 1
3) If the lower layer is not provided, the print density and density uniformity are lowered, and the strength of the coating film is also low (Comparative Example 1).
A film containing no organic boron compound polymer in the lower layer also has a low coating strength. If it is more than 30% by weight, the ink absorbency is lowered and the blurring is lowered. (Comparative example 2)

[0034]

EFFECT OF THE INVENTION The ink jet recording paper of the present invention has a strong surface, clear printing and excellent ink absorbency. By improving the printing density and uniformity, the drawbacks of conventional recording papers are eliminated, and It enables a high-resolution, high-speed, general-purpose inkjet printing system.

Claims (1)

[Claims] 1. A support, a lower layer formed on one surface of the support and containing an organic boron compound polymer as a main component, and laminated on the lower layer, and amorphous fine powder silica, the organic boron. An ink jet recording sheet comprising an ink receptive coating layer containing a water-soluble resin having a hydroxyl group capable of reacting with a compound polymer and a cationic polymer as main components.