JP2000272231A - Ink jet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an ink jet recording sheet of superior resistance to curling, whiteness and gloss. SOLUTION: An ink jet recording sheet is provided with a base sheet and an ink acceptive layer of aqueous ink absorbability formed on one face of the base sheet, and the base sheet is provided with a core base and a resin film layer laminated at least on one face of the core base. The base sheet is also provided with resin film layers laminated on both faces of the core base formed of a paper.

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 having excellent curl resistance, whiteness, and gloss, and more particularly to a photo-like image receiving paper suitable for performing photographic recording.

[0002]

2. Description of the Related Art Conventionally, as an output print of a computer or a word processor, a wire dot recording system,
Various systems such as a thermosensitive coloring recording system, a thermosensitive transfer recording system, a thermosensitive sublimation transfer recording system, an electrophotographic recording system, and an ink jet recording system have been developed. Among them, the ink jet recording method has the features that plain paper can be used as a recording sheet, printing cost is low, the apparatus is compact, there is no noise, and high-speed recording is possible. For this reason, attention has been paid to the use as a printer for quickly and accurately outputting image information such as characters and figures produced by a computer or the like. Also,
Due to the ease of colorization and the sharpness of the picture, there is an increasing demand for recording image information produced by a computer on a recording sheet by an ink jet printer and using this as a document.

In general, an ink jet printer ejects recording ink from a nozzle by pressure of a fine piezoelectric element (piezo element) or air pressure (bubble jet) generated by heating a thermal head, and adheres to a recording sheet. The recording is performed by causing the recording. For this reason, as a recording ink used for ink jet recording, an ink that is difficult to dry is used in order to prevent ink ejection failure from nozzles due to an increase in viscosity due to drying of the ink. In general, the ink component generally has a dye, a polymer, an additive, and the like dissolved in water and alcohol. Therefore, a recording sheet on which recording is performed by an inkjet printer is required to absorb the liquid component of the attached ink and dry and solidify the ink. For this reason, a recording sheet in which a water-absorbing ink-receiving layer is formed on a base sheet to enhance the ink absorbency is used.

Heretofore, an ink jet recording sheet has been used in which an ink receiving layer is provided on a paper base material such as a coated paper.
There is a problem that curls and wrinkles easily occur. Alternatively, when the ink receiving layer is water-based, when the ink receiving layer is coated on a paper substrate, the water-based ink permeates, and wrinkles and curls occur during drying. In addition, there is a problem that glossiness that can be called photographic quality cannot be obtained due to unevenness on the surface of the paper substrate.

[0005]

In order to solve such a problem, even if the curl is removed by humidity control or the like, if the product is stored in a high-humidity environment, the shrinkage stress generated at the time of coating will not increase. Therefore, there is a problem that curling occurs. Furthermore, the formation of the paper comes out on the surface of the sheet,
Appearance and surface smoothness deteriorate, glossiness decreases,
There was a problem that it had an adverse effect on printing.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an ink jet recording sheet having excellent curl resistance, whiteness, and gloss.

[0007]

In order to achieve the above object, the present invention provides an ink jet recording apparatus comprising a base sheet and an aqueous ink-absorbing ink receiving layer provided on one side of the base sheet. A sheet, wherein the base sheet includes a core substrate made of paper and a resin film layer laminated on at least one surface of the core substrate. The base sheet includes a resin film layer laminated on both sides of a core base made of paper.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing one embodiment of the recording sheet of the present invention. In FIG. 1, a recording sheet 1 includes a paper core substrate 2,
The ink receiving layer 5 is provided on a base sheet 4 made of a resin film layer 3. FIG. 2 is a sectional view showing an embodiment of an application of the present invention. In FIG. 2, a recording sheet 1 is provided with an ink receiving layer 5 via a primer layer 6 on a base sheet 4 in which resin film layers 3 are laminated on both sides of a paper core base 2.

(Core substrate) The substrate sheet 4 used in the recording sheet of the present invention is obtained by laminating a resin film layer 3 on one or both sides of a core substrate 2 made of paper. Here, as the paper used for the core substrate, wood pulp is mainly used, but synthetic fibers, inorganic fibers, and the like may be mixed as necessary. As additives, sizing agents such as rosin, alkyl ketene timer, alkenyl succinic acid, clay,
Fillers such as talc, calcium carbonate, etc., paper strength agents such as polyacrylamide and starch, fixing agents such as sulfate bands and cationic polymers, wet strength agents such as melamine resins, polyamide-polyamine-epichlorohydrin resins, dyes, fluorescence A dye or the like may be internally added. During papermaking, a sizing agent such as a water-soluble polymer such as starch and polyvinyl alcohol, and a sodium salt of a styrene-maleic anhydride copolymer alkyl ester may be applied by a size press.

In addition, the following synthetic paper may be used. As the synthetic paper, use a synthetic paper made of a polyolefin-based or polystyrene-based synthetic paper, particularly a synthetic paper provided with a paper-like layer containing micropores, or a single-layer or composite film having micropores. In particular, those having fine pores in a polypropylene film are preferable. Alternatively, synthetic paper in which a thin film layer of a resin containing no pigment is formed on a microvoid film may be used. With this thin film layer, the gloss and smoothness of the synthetic paper can be improved.

This synthetic paper is obtained by forming a mixture of a resin such as polyester or polyolefin and inorganic fine particles such as barium sulfate in a sheet shape on a microvoid film stretched uniaxially or biaxially to form a thin film layer. Although the resin can be obtained by co-extrusion, it is preferable that the resin for forming the thin film layer is simultaneously stretched when the microvoid film is stretched. The fine pores can be formed, for example, by stretching a synthetic resin in a state containing a fine filler.

Specific examples of synthetic paper include commercially available synthetic paper “Yupo” (manufactured by Oji Yuka Synthetic Paper Co., Ltd.), Toyopearl SSP4255 (manufactured by Toyobo Co., Ltd.), and W900.
(Manufactured by Diafoil Hoechst Co., Ltd.) and Crispar (manufactured by Toyobo Co., Ltd.).

The thickness of the core substrate is not particularly limited, but is usually, for example, about 5 to 200 μm.

(Resin Film Layer) As the resin film layer 3 laminated on one or both sides of the core substrate, a polyethylene film such as a polyester film, a polycarbonate film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polypropylene film, Polyether ether ketone film, polyamide film, polyether sulfone film, acrylic film, polyvinyl chloride film, polystyrene film, polyvinyl alcohol film, diacetate film, triacetate film, polyimide film, etc. can be exemplified, and the material is not particularly limited. ,In particular,
Polyethylene films such as polyester films, polycarbonate films, polyethylene terephthalate films, and polyethylene naphthalate films, polypropylene films, polyetheretherketone films, polyamide films, and polyethersulfone films are preferred. In particular, when a transparent resin film is used,
It is preferable in that the glossiness is improved. The thickness of these resin film layers is about 5 to 200 μm.

(Joining Method) Examples of the joining method of the core substrate 2 and the resin film layer 3 include, for example, pasting using a conventionally known adhesive, pasting using an extrusion laminating method,
Adhesion by thermal bonding and the like can be mentioned. Specific examples of the adhesive include an ethylene-vinyl acetate copolymer, an emulsion adhesive such as polyvinyl acetate, a water-soluble adhesive such as a polyester containing a carboxyl group, and the like, and as an adhesive for lamination, Adhesives such as an organic solvent solution type such as a polyurethane type and an acrylic type can be used. Preferably, using such an adhesive, it is more preferable to bond the core substrate 2 and the resin film layer 3 via an adhesive layer having a thickness of 1 to 50 μm. When a substrate sheet in which a resin film layer is laminated on one side of a paper core substrate is used, cushioning and smoothness when used as a recording sheet are improved. Further, when a sheet obtained by laminating a resin film layer on both sides of a paper core base material is used as the base sheet, a recording sheet that is further excellent in anti-curl resistance can be obtained.

(Ink-Receiving Layer) As the ink-receiving layer 6 provided on the base sheet 4 thus laminated, various types of receiving layers such as a porous layer type may be used, which are of a water-absorbent type. Although it is possible, it is preferable to mainly use a water-soluble resin or a water-absorbing resin. The water-soluble resin is soluble in water or a mixed solvent of water and alcohol, and conventionally known various resins are used. For example, polyvinyl alcohol, polyvinylpyrrolidone, poly (meth) acrylic acid,
Cellulosic resins (CMC, HEC, HPC, etc.), polyacrylamide, polyethylene oxide, polyethylene glycol, polyvinyl acetal resins, polyvinyl methyl ether, polyamine, polyethylene imine,
Water-soluble resins such as casein, gelatin, and starch, and / or at least one of copolymers thereof, cations, and anion-modified products are used.

On the other hand, as the water-absorbing resin, the water-soluble resin as described above is crosslinked to make it water-absorbing and water-insoluble, and the water-soluble resin is partially crosslinked or grafted. And those crosslinked by a crosslinking agent, heating or ionizing radiation after coating. Other examples include copolymers of a hydrophilic monomer and a hydrophobic monomer, such as a water-absorbing alkyd resin, polyester resin, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer resin, NBR resin, and SBR resin. , Polyurethane resins, acrylic resins, polyamides and the like are used alone or as a mixture or a modified product. The modified product is, for example, one obtained by copolymerizing or grafting a hydroxyl group, a carboxylic acid, a sulfonic acid, a quaternary ammonium salt-containing monomer or an oligomer, and increasing the hydrophilicity.

Further, on the surface or inside of the ink receiving layer,
A phosphate-based aliphatic hydrocarbon or a sulfonate-based aliphatic hydrocarbon antistatic agent may be contained. Examples of these antistatic agents include alkyl, alkene, alkane, phosphoric acid having an alkyne chain, sulfonic acid sodium salt and ammonium salt. There are liquid and solid forms. Liquid antistatic agents are easily converted to inks, and solid antistatic agents have an effect on storage performance such as blocking resistance. Since these antistatic agents have high hydrophilicity, they are well compatible with inks, are effective in improving image clarity, and do not show a decrease in image clarity due to storage. In addition, since the sheet has high moisture absorbency and water retention, moisture can be retained inside the recording sheet even in a low-humidity environment, so that curling due to moisture release can be prevented.

Examples of a method for applying these antistatic agents to the ink receiving layer include top coating and spraying on the ink receiving layer and mixing with the ink receiving layer resin. The overcoating or spraying is preferably performed after diluting to about 1 to 30% (% by weight) with a single solvent or a mixed solvent of water, alcohol, and other organic solvents. In addition, in the case of mixing with the ink receiving layer resin, 0.1 to 0.1 parts of the receiving layer resin component is used.
It is preferable to mix about 1% to 20% (weight%).
Particularly preferably, about 1 to 10% (% by weight) is mixed. When the mixing ratio of the antistatic agent is small, the antistatic effect is not exhibited. On the other hand, if the mixing ratio of the antistatic agent is too large, the compatibility with the resin of the receiving layer is not so good, so that bleed out occurs on the surface of the receiving layer, and the transparency and the storability of the recording sheet are reduced. Incidentally, the antistatic agent can be applied as a separate layer on the ink receiving layer together with the resin binder.

For the purpose of improving blocking resistance, coating strength, and adhesion, various aqueous polymers such as alkyd resins, polyester resins, polyvinyl acetate, and vinyl chloride-vinyl acetate copolymer resins are used in the above composition. , NB
R resin, SBR resin, polyurethane resin, acrylic resin, polyamide and the like can be added alone or as a mixture or as a modified product. In particular, the organic particles having a diameter of 5 to 80 μm of primary particles and the inorganic particles of 5 to 20 μm in diameter of secondary particles are 0.1 to
There is an effect when added in the range of 10% (% by weight). Also,
Additives, inorganic compounds, and the like that enhance dye fixing properties can also be added. In addition, various surfactants, antioxidants, ultraviolet absorbers, antifoaming agents, various types of highly hydrophilic modified oils, and the like can be mixed and used as long as the object of the present invention is not hindered.

The above-described composition of the ink-receiving layer may be coated on the substrate sheet by various conventionally known methods, for example, gravure coat, gravure reverse coat, roll coat, wire bar coat, and the like. Any method such as blade coating, knife coating, air knife coating, comma coating, slot die coating, and dip coating may be used. The thickness applied to the substrate sheet using these methods is 0.1 to 50 μm when dried,
Preferably, the thickness is 3 to 30 μm. This thickness is
If it is less than 0.1 μm, the ink absorption amount is not sufficient,
On the other hand, if it exceeds 50 μm, it is not preferable because it only increases economic disadvantages.

(Primer Layer) A primer layer 6 may be formed between the base sheet 4 and the ink receiving layer 5. Such a primer layer is for improving the adhesiveness between the base sheet and the ink receiving layer, and is formed of a polyester resin, a polyurethane resin, an acrylic resin, a polyethylene resin, a polypropylene resin, an epoxy resin, or the like. And the thickness is 0.1-25
It is preferably about μm.

[0023]

(Ink receiving layer coating liquid)

 Polyvinyl alcohol resin alone (PVA217 manufactured by Kuraray Co., Ltd., 10% by weight aqueous solution)

Example 2 A recording sheet was prepared in the same manner as in Example 1 except that a core substrate was used in which resin film layers were bonded to both sides of a core substrate.
In this case, an OPP film having a thickness of 38 μm was used as a resin film to be bonded to both surfaces of the core substrate.

Example 3 A recording sheet was prepared in the same manner as in Example 2 except that a polyethylene terephthalate film having a thickness of 25 μm was used as a resin film to be bonded to both surfaces of the core substrate.

(Comparative Example 1) A base sheet having a thickness of 11
A recording sheet was prepared in the same manner as in Example 1 except that 0 μm pulp paper (manufactured by Oji Paper Co., Ltd.) was used.

(Comparative Example 2) A base sheet having a thickness of 11
A recording sheet was prepared in the same manner as in Example 1, except that a 0 μm polyethylene terephthalate film was used.

Test patterns were printed on the recording sheets of the above Examples and Comparative Examples using an ink jet printer (BJC-600J manufactured by CANON), and the results shown in Table 1 below were obtained. In addition, the evaluation method of each performance shown in Table 1 is as follows.

(1) Curling Resistance After the recording sheet was stored in an environment of 40 ° C. and 80% for 48 hours, and further left for 1 hour in an environment of 23 ° C. and 40%, the maximum value of the curl state of each corner was measured. Was measured. ：: 10 mm or less △: 30 mm or less ×: 30 mm or more

(2) Gloss The specular gloss at 45 degrees was measured based on JIS Z8741. ：: 30% or less ×: 30% or more

(3) White hiding property The haze value was measured (according to JIS K 7105). ：: 30% or more ×: 30% or less

[0032]

[Table 1]

[0033]

As described above, the recording sheet according to the present invention uses a laminated base material in which a core substrate made of paper and a resin film layer are laminated, and is resistant to the flexibility of the adhesive used in the bonding. Curling properties are improved. Further, by using the bonded base material, the surface of the receiving layer provided on the base material can have sufficient glossiness without being affected by the uneven surface of the core base material made of paper.
In addition, sufficient whiteness can be obtained as compared with the case where a substrate composed of a single film is used.

[0034]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a recording sheet of the present invention.

FIG. 2 is a cross-sectional view showing an embodiment of an application of the recording sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording sheet 2 Core base material 3 Resin film layer 4 Base material sheet 5 Ink receiving layer 6 Primer layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 FC06 2H086 BA15 BA21 BA24 4F100 AK01C AK01D AK21B AK42C AK42D AT00A BA04 BA07 BA10B BA10D BA13 CC00B DG10A GB90 JD14B JL04 JN21

Claims (2)

[Claims] 1. A sheet for ink jet recording comprising a base sheet and an aqueous ink-absorbing ink-receiving layer provided on one surface of the base sheet, wherein the base sheet is made of paper An ink jet recording sheet comprising: a material; and a resin film layer laminated on at least one surface of the core substrate. 2. The ink jet recording sheet according to claim 1, wherein the base sheet includes resin film layers laminated on both sides of a core base made of paper.