JPH06239015A - Sheet for ink-jet recording - Google Patents

Abstract

PURPOSE:To provide a sheet for ink-jet recording, which has the improved ink absorbing property and high transparency and can perform printing having high picture quality. CONSTITUTION:A sheet for ink-jet recording has a sheet-shaped supporting body (e.g. transparent Mylar film of 50mum) and an ink accepting coated layer, which is formed on at least one surface of the sheet. In this sheet, the ink accepting coated layer (applied amount: about 10g/m<2>) contains polyacrylic acid or the added body of polymethacrylic acid and polyethylene glycol as main components. The polymerization degree of the polyethylene glycol is 4000 or more. The sheet for ink-jet recording such as this is obtained.

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 use in printers, copying machines and the like, which uses water-based ink, and is excellent in color developability, ink absorbability, high transparency, and image uniformity. The present invention relates to an improved color inkjet recording sheet having excellent resolution.

[0002]

2. Description of the Related Art Ink jet printers that use water-based inks have improved performance, especially image quality such as print speed, resolution, and gradation, so that high-speed ink absorption, high absorption capacity, and high-density printing can be performed even on recording sheets. In addition to the above, there has been a demand for a color inkjet recording sheet having a uniform density, higher image quality, and a transparent ink-receptive coating layer.

For example, a highly transparent recording sheet for OHP (Overhead Projector) or the like is provided with a transparent ink absorbing layer on a transparent support. Since such a support generally has no ink absorbency, the ink absorbency is fast, and in order to print at a high density, for example, JP-A-61-181679 discloses carboxymethyl cellulose and polyethylene oxide. Blends with water-soluble cellulose and polyvinylpyrrolidone in JP-A-61-193879, and JP-A-6-196830.
JP-A 2-160270 describes the use of a polymer complex of a basic polymer and a phenol resin.

However, in recent years, applications have been diversified such as support for the output of personal computers. In such a situation, it is desired to obtain an ink jet recording sheet having high density and uniform high image quality printing, having a high ink absorption speed, and not impairing the color development of a dye, and having a high image resolving power and storability. ing.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides an ink jet printer using a liquid ink, which has a high ink absorption speed, can print a sharp high-resolution image, and is excellent in image density uniformity. The present invention intends to provide an inkjet recording sheet satisfying the above conditions.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted various studies in order to achieve the above-described good print quality and good ink absorbability, and as a result, a sheet-like support,
In an inkjet recording sheet having an ink-receptive coating layer formed on at least one surface of the sheet, the ink-receptive coating layer is mainly composed of an adduct of polyacrylic acid or polymethacrylic acid and polyethylene glycol. The present invention has been completed by finding that it is contained and is obtained by setting the degree of polymerization of the polyethylene glycol to 4000 or more.

According to the present invention, a sheet-like support ink-receptive coating layer containing a resinous adduct having high water absorption and good transparency is provided on at least one surface of the sheet-like support. It is possible to print a sharp high-resolution image having a high absorption speed, a large absorption capacity, and a high speed, and further, printing with excellent image density uniformity.

The sheet-like support used in the present invention may be a conventionally known support as a transparent sheet-like support. For example, polyester film, acetate resin film, acrylic resin film, polycarbonate resin film, cellophane, etc. may be mentioned. In addition, neutral or acidic high-quality paper mainly composed of normal natural pulp, medium-quality paper, recycled paper coated paper, art paper, etc., as well as calcium carbonate, calcined clay, diatomaceous earth, talc, silica Is a uniaxially or biaxially stretched multi-layered thermoplastic resin film containing 8 to 65% of an inorganic fine pigment such as
In addition to the three-layer structure in which the axially stretched paper-like layers are bound, depending on the application, the paper-like layer and the base material layer may have, for example, four or more layers including a surface layer for the purpose of improving whiteness. This is a biaxially stretched multi-layered polyolefin sheet containing finely divided inorganic pigments. Synthetic paper manufactured from opaque paper to semi-transparent trace paper depending on the amount and type of pigment added. As the plastic resin, polyolefin resin, for example, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer as a main component, in addition, other thermoplastic resins such as polystyrene, acrylic ester copolymer Used as a mixture. In addition, synthetic and natural resin films can be used. The sheet-shaped support preferably has a thickness of 10 to 200 μm and a basis weight of 10 to 200 g / m ² .

The adduct of polyacrylic acid or polymethacrylic acid and polyethylene glycol used in the ink-receptive coating layer of the present invention is, for example, "INDUSTRIAL AND
ENGINEERING CHEMISTRY '' Vol.51, No.11, NOVEMBER 19
59, pages 1361-1364, low molecular weight polyethylene glycol to polyethylene oxide having a molecular weight of 8 million and polyacrylic acid resin each dissolve in water alone, but precipitate when mixed in an aqueous solution. Occurs. It is known that the precipitate is dried to form a transparent, flexible, homogeneous, water-insoluble, water-absorbing adduct. The formation of the adduct in this solution can be prevented by adding a water-soluble solvent such as acetone or acetonylacetone, and the adduct is formed by removing the solvent.
In addition, it has been found that the use of sodium or ammonium polyacrylic acid prevents the formation of an adduct, and acidification thereof produces an adduct.

The polyacrylic acid or polymethacrylic acid used in the present invention is not particularly limited,
Molecular weights of 1,000 to 100,000 are preferably used. Further, the molecular weight of polyethylene glycol is preferably 4000 or more, and if it is less than this, the resolution of the printed image is lowered. The mixing ratio of polyacrylic acid or polymethacrylic acid and polyethylene glycol is selected by the glass point transfer and water absorption of the coating film, but the ratio of polyacrylic acid or polymethacrylic acid and polyethylene glycol is 95: 5 weight. It is desirable to select between 5% and 5: 95% by weight. If used outside the above range, the function as an adduct of polyacrylic acid or polymethacrylic acid and polyethylene glycol is insufficient, and problems occur in printing performance, water resistance of the coating film, and the like.

In addition to the above-mentioned adduct of polyacrylic acid or polymethacrylic acid and polyethylene glycol, the ink-receptive coating layer of the present invention can maintain transparency in applications requiring transparency such as OHP. For other purposes, it is possible to mix and use a pigment that is used in inkjet recording as a pigment to improve performance such as clearness of printing and gives a clear image. For example, silica, aluminum silicate, calcium silicate, kaolin, clay, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, aluminum hydroxide, diatomaceous earth, zinc oxide, titanium oxide, barium sulfate, inorganic pigments such as acid clay, urea. Organic pigments such as a series resin pigment, an ethylene series resin pigment, a styrene series resin pigment, and an acrylic series resin pigment are used alone or in combination.

In the ink-receptive coating layer of the present invention, in addition to the above-mentioned adduct of polyacrylic acid or polymethacrylic acid and polyethylene glycol, an aqueous resin is mixed and used for improving the strength of the coating film. Good, for example, polyvinyl alcohol and derivatives modified with silanol groups, etc., oxidized starch, and modified starches such as etherification, esterification and grafting, cellulose derivatives such as gelatin, casein, carboxymethylcellulose, polyvinylpyrrolidone, water-soluble Water-soluble resins such as polyester resins and water-dispersible resins such as styrene / butadiene copolymers, acrylic ester copolymers, polyvinyl acetate, ethylene / vinyl acetate copolymers may be used alone or in combination.

In addition, pigment dispersants, defoamers, colorants, antioxidants, ultraviolet absorbers, viscosity modifiers,
A cross-linking agent, a cationic resin for improving the water resistance of the printed matter after inkjet recording, and the like are appropriately used according to the production conditions, the printing quality, and the required performance. The amount of the pigment used in the ink-receptive coating layer of the present invention is in the range of 5 to 90% by weight, preferably 10 to 80% by weight. 90 pigments
If it is used in excess of weight%, the strength will be reduced, which is not preferable.
If it is less than 20% by weight, the ink absorbency is lowered,
The ink dryness becomes insufficient and the image quality deteriorates.

In the ink-receptive coating layer of the present invention, the above-mentioned constituents are uniformly dispersed in water by a conventional method to prepare a coating solution, which is used in, for example, a bar coater, a blade coater, an air knife coater, a gravure coater or the like. The coating amount is ^{2 to 20} g / m ² on at least one surface of the support by the coating method.
Providing at the rate of. When the coating amount is less than 2 g / m ² , the image uniformity and the image density are insufficient, and the coating amount is 20 g / m ²
If the amount is larger than the above range, the strength of the coating film is lowered and the performance is saturated, resulting in a high price, which is not preferable.

[0015]

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 examples,% means solid content% by weight. Example 1 A coating material 1 was prepared at a concentration of 20% by weight on a transparent Mylar film having a thickness of 50 μm, coated at a solid content of 10 g / m ² and dried to prepare an ink jet recording sheet having an ink receptive coating layer. did. Paint-1 Polyacrylic acid (AC-10L: manufactured by Nippon Pure Chemical) 60% Polyethylene oxide (molecular weight 50,000: manufactured by Meisei Chemical) 40%

Example 2 Paint-2 was prepared in a concentration of 20% by weight, coated on a transparent Mylar film having a thickness of 50 μm at a rate of 8 g / m ^{2 as} a solid content, dried, and an ink jet recording having an ink receptive coating layer. I made a sheet for. Paint-2 Polymethacrylic acid (AC-20H: manufactured by Nippon Pure Chemical) 80% Polyethylene glycol (molecular weight 4,000: manufactured by Tokyo Kasei) 20%

[0017] EXAMPLE 3 Paint -3 adjusted to a concentration of 20 wt%, the coating at a rate of 7 g / m ² by solid content in the wood-free paper of 65 g / m ^2, and dried, with an ink receptive coating layer An inkjet recording sheet was prepared. Paint-3 Polyacrylic acid (AC-10L: manufactured by Nippon Pure Chemical) 30% Polyethylene glycol (molecular weight 4,000: manufactured by Tokyo Kasei) 30% Amorphous fine silica (Fineseal: manufactured by Tokuyama Soda) 40%

Comparative Example 1 A transparent Mylar film having a thickness of 50 μm was prepared with a coating material 4 having a concentration of 20% by weight, and a solid component was applied at a rate of 10 g / m ² and dried to prepare an ink-receptive coating layer for ink jet recording. Created a sheet. Paint-4 polyacrylic acid (AC-10L: manufactured by Nippon Pure Chemical) 100%

Comparative Example 2 Paint-5 was prepared in a concentration of 20% by weight and coated on a transparent Mylar film of 50 μm in a solid content of 10 g / m ² .
An ink jet recording sheet having an ink receptive coating layer was prepared by drying. Paint-5 Polyethylene glycol (molecular weight 4,000: manufactured by Tokyo Kasei) 30%

Comparative Example 3 Paint-6 was prepared in a concentration of 20% by weight, coated on a fine paper of 65 g / g at a solid content of 7 g / m ² and dried, and an ink jet recording having an ink receptive coating layer. I made a sheet for. Paint-5 Polyacrylic acid (AC-10L: manufactured by Nippon Pure Chemical Co., Ltd.) 60% Polyethylene glycol (Molecular weight 4100: manufactured by Tokyo Kasei) 40%

The recording characteristics of the ink jet recording sheet are as follows: ink jet printer (BJ820 manufactured by Canon Inc.)
J) was used for printing. The image density was measured by using a Macbeth densitometer, and a plurality of lines of heavy color were printed to visually evaluate bleeding to determine the resolution. For coating strength, immerse the coating layer in water,
The rubbing coating was observed with a finger. The evaluation is indicated by ◯ for excellent performance, Δ for general quality, and x for defects having problems in use.

[0022]

[Table 1]

As is clear from Table 1, an ink receptive coating layer containing an adduct of polyacrylic acid or polymethacrylic acid and polyethylene glycol as a main component is provided on at least one surface of the sheet-like support. As a result, it is possible to obtain an inkjet paper having a clear image by inkjet recording, having contrast, and having good dot shape, resolution, water resistance of the coating film, and ink absorbency.
(Examples 1 to 3) In the ink-receptive coating layer containing no adduct, the water resistance was lowered, the dot shape was insufficient (Comparative Examples 1 and 2), and when the polyethylene glycol had a low molecular weight, , Print density, and resolution are reduced. (Comparative example 3)

[0024]

INDUSTRIAL APPLICABILITY The inkjet paper of the present invention has clear printing, excellent ink absorption, good dot shape, and improved ink absorption and resolution, thereby adding a new function to the conventional recording sheet. This enables the production of high-quality, high-resolution inkjet recording sheets.

Claims (1)

[Claims] 1. An inkjet recording sheet having a sheet-like support and an ink-receptive coating layer formed on at least one surface of the sheet, wherein the ink-receptive coating layer is polyacrylic acid or polymethacrylic. It contains an adduct of an acid and polyethylene glycol as a main component, and the degree of polymerization of the polyethylene glycol is 40.
An inkjet recording sheet characterized by having a size of 00 or more.