JP2001039011A - Double side ink jet recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress penetrating and soaking of a coating liquid for a glossiness regulating layer to an ink receiving layer by incorporating a weak cationic or anionic resin in a binder resin of the regulating layer in a double side ink jet recording medium obtained by laminating an ink receiving layer and the regulating layer on both surfaces of a support. SOLUTION: In the double side ink jet recording medium obtained by laminating glossiness regulating layers on uppermost surfaces of ink receiving layers coating both surfaces of a support, a weakly cationic or anionic resin is contained in a binder resin of the regulating layer. The binder resin of the receiving layer is prepared by incorporating three components of an emulsion resin, at least one type of water soluble resin selected from a starch and a cellulose derivative and a water soluble resin except the starch and the cellulose derivative. The binder resin is obtained by preferably incorporating 10 to 75 pts.wt. of the water soluble resin and 15 to 75 pts.wt. of the another water soluble resin within 100 pts.wt. of the emulsion resin.

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 medium, and more particularly, to an ink receiving layer coated on both sides of a same support, and a glossiness adjusting layer laminated on the ink receiving layer. More specifically, the present invention relates to a double-sided inkjet recording medium.

[0002]

2. Description of the Related Art Ink-jet recording systems for printing on a recording medium with an aqueous ink have been widely used in recent years because they have various features such as high speed, low noise, easy colorization, and clear images. Is increasing. As a recording medium that effectively reflects the features of this ink jet recording system, it has the property of sharpening the image while sufficiently absorbing the water-based ink on the surface of a support such as paper made mainly of pulp. Ink-jet recording paper having an ink receiving layer laminated thereon. In general, the ink receiving layer uses a pigment represented by silica as an ink receiving agent, and disperses the pigment in a binder resin such as carboxyl group-modified PVA (polyvinyl alcohol). It is laminated by coating. Further, a glossiness adjusting layer is laminated on the ink receiving layer as needed in order to impart gloss to the surface of the recording paper. As such ink jet recording papers, those having an ink receiving layer laminated on one side of a support and those laminated on both sides, that is, those for single side recording and both side recording are commercially available.

[0003]

By the way, ink jet printers generally used as ink jet recording systems have been supplied at a lower cost in recent years, and on-demand printing (for example, album applications) has become clearer as vivid colors become familiar. And pamphlet applications). When an image recorded on both sides is required for such an application, to apply an ink jet recording sheet for single-sided recording, two sheets of paper are stuck to each other or two sheets are back to back to clear. The method of binding to a file was adopted. However, such a method is complicated, and has a problem that wrinkles are generated at the time of bonding and a printed image is deteriorated at the time of storage due to the influence of the glue used for bonding. Is preferred.

However, in the conventional double-sided ink jet recording medium in which a water-soluble polymer is used as a main binder resin, an ink receiving layer is coated on both sides of a support, and a glossiness adjusting layer is laminated thereon. It is difficult to say that the water resistance of the receiving layer is sufficient. For this reason, when the gloss adjusting layer is formed on the back side of the support by the casting method, the water generated in the coating process of the gloss adjusting layer is absorbed by the ink receiving layer on the front side, and the gloss on the front side is absorbed. In some cases, the adhesiveness of the interface with the adjustment layer was impaired, causing layer destruction and the like.
Therefore, the conventional inkjet recording paper for double-sided recording has a problem that yield and productivity are reduced due to layer destruction at the interface between the ink receiving layer and the glossiness adjusting layer. Therefore, the present invention has been made in view of the above circumstances, and a double-sided ink jet recording medium capable of preventing layer destruction at an interface between an ink receiving layer and a glossiness adjusting layer and improving yield and productivity. It is intended to provide.

[0005]

The present inventors have conducted various studies on an ink jet recording medium having recording surfaces on both sides of a support, and as a result, have found that the binder resin of the glossiness adjusting layer has a weak cationic or anionic property. By using a resin, it is possible to suppress the penetration of the coating liquid for the glossiness adjustment layer into the ink receiving layer and to suppress the penetration, and it is possible to improve the adhesiveness of the glossiness adjustment layer to the ink receiving layer. It has been found that destruction of the layer at the interface between the ink receiving layer and the glossiness adjusting layer laminated thereon can be prevented.

That is, the double-sided ink jet recording medium of the present invention has been made based on the above findings, and has an ink receiving layer containing a pigment and a binder resin on both sides of a support, and a glossy layer on the ink receiving layer. An ink jet recording medium comprising a glossiness adjusting layer laminated thereon, wherein the binder resin of the glossiness adjusting layer contains a weak cationic or anionic resin.

In a more preferred embodiment for exhibiting the effects of the present invention, the binder resin of the ink receiving layer is composed of an emulsion resin (A) and at least one water-soluble resin selected from starch and a cellulose derivative. It is characterized by containing three components, a resin (B) and a water-soluble resin (C) other than starch and a cellulose derivative. Hereinafter, preferred embodiments of the present invention will be described in detail.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The double-sided ink jet recording medium of the present invention has a form in which a glossiness adjusting layer is laminated on each outermost surface of an ink receiving layer coated on both sides of a support. The ink receiving layer and the gloss adjusting layer are laminated at least one layer at a time, but either one or more layers may be laminated, or two or three layers may be laminated. . Hereinafter, the constituent materials of the ink jet recording medium of the present invention will be described in detail.

(1) Support The support for coating the ink receiving layer and the glossiness adjusting layer used in the present invention on both sides is LBKP, NB.
Chemical pulp such as KP, GP, PGW, RMP, TMP,
The main components are wood pulp such as mechanical pulp such as CTMP, CMP and CGP, waste paper pulp such as DIP, and synthetic fiber pulp such as polyethylene fiber, and pigments and sizing agents, fixing agents, retention improvers, and paper strength agents. One or more of various additives commonly used in papermaking such as etc. may be mixed by using one or more as needed, and the base paper manufactured by various apparatuses such as fourdrinier paper machine, circular net paper machine, twin wire paper machine, and the like. This base paper has starch,
Art paper, coat paper, cast coat made of baryta paper used for size paper of polyvinyl alcohol, casein, gelatin, etc., base paper provided with an anchor coat layer, photographic printing paper, etc. Coated paper such as paper can be used.

The base paper and the coated paper may be provided with an ink receiving layer as they are, or the recording medium produced using this support may be provided with an ink receiving layer in order to obtain a more photographic paper texture. It is also possible to use a material in which the smoothness of the support and the coating property of the ink receiving layer are improved by using a calender such as a machine calender, a TG calender, and a soft calender at the stage before the layer coating.

Further, as an approach from a laminate material on a support, a material which is made porous from the beginning so that the air permeability does not increase excessively, or a material which is laminated with an extremely thin film and becomes porous by heating or the like. It is also possible to use synthetic resins such as polyolefins, polyethylene, polypropylene, polyester, nylon, rayon, polyurethane, etc., and synthetic resin laminate base paper using these film materials.

The air permeability of the support used in the present invention is determined by the method described in J. TAPPI Paper Pulp Test Method No. in order to maintain the air permeability of the recording medium after coating the glossiness adjusting layer within a certain level. .5 ”according to the Oken type air permeability test method.
Preferably 10 seconds to 1000 seconds, more preferably 10 seconds
It is most preferable that the time is from second to 400 seconds and from 10 seconds to 100 seconds. An ink jet recording medium using a support having an air permeability of more than 1000 seconds has an air permeability after the ink receiving layer is applied which does not become lower than this. It is not preferable because it may cause a problem of strength or cause a decrease in recording quality such as a decrease in ink absorption characteristics of the produced inkjet recording medium.

In addition, the smoothness of both coated surfaces of the support impairs the hardness of the support in order to maximize the design properties (to make it closer to photographic paper) of the recording medium produced thereby. It is preferable to use as high a method as possible.
The value of the smoothness is a value according to the Oken type smoothness test method defined in “J. TAPPI Paper Pulp Test Method No. 5,” preferably 100 seconds or more, and more preferably 5 seconds or more.
Most preferably, it is at least 00 seconds and at least 1500 seconds.

Further, regarding the stiffness of the support, if the support is too soft or too hard, a problem may occur in the paper feeding process to the printer.
I pulp test method No. 40 ”at a temperature of 20 ° C. and 65% RH according to the Gurley stiffness test method specified in“ 40 ”, preferably in the range of 400 mN to 3600 mN in the vertical direction, 200 mN to 1800 mN in the horizontal direction, and 800 mN to 2500 mN in the vertical direction. Most preferably, it is in the range of 400 mN to 1000 mN in the lateral direction.

(2) Ink-Receiving Layer Pigment In the ink-receiving layer in the present invention, one or more commonly used pigments that are insoluble or hardly soluble in water can be used. For example, light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate,
Satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, colloidal alumina, pseudo boehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrohaloisite, magnesium carbonate, magnesium hydroxide, etc. Examples include white inorganic pigments, styrene-based plastic pigments, acrylic-based plastic pigments, polyethylene, microcapsules, organic pigments such as urea resins, and melamine resins.

Among the above, as the white pigment contained as a main component in the ink-receiving layer, a porous inorganic pigment is preferable because the ink-jet ink is excellent in drying property and absorption property, and a porous synthetic amorphous pigment is used. Examples include silica, porous magnesium carbonate, and porous alumina. In the present invention, sedimentation-type and gel-type porous amorphous silica or porous alumina having a specific surface area of about 200 to 600 g / m ² that satisfies both printing quality and storage stability (room storage stability and direct sunlight) are used. It is preferred to do so.

Binder Resin As the binder resin constituting the ink receiving layer of the present invention, a conventionally used water-soluble or water-dispersible resin can be used. However, in order to synergistically exert the effects of the present invention, as a binder resin for the ink receiving layer, an emulsion resin (A), and at least one water-soluble resin (B) selected from starch and a cellulose derivative, It is preferable to use three components of the water-soluble resin (C) other than the starch and the cellulose derivative in an appropriate mixing ratio.

(A) Emulsion resin Emulsion resin (A) is a conjugated diene copolymer emulsion such as maleic anhydride resin, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer; acrylic ester and methacrylic ester. Acrylic polymer emulsions such as acid ester polymers or copolymers; Vinyl polymer emulsions such as ethylene-vinyl acetate copolymer; or functionalities of these various polymers by monomers containing functional groups such as carboxyl groups Group-modified polymer emulsions; copolymer resin emulsions such as melamine resin, urea resin, polymethyl methacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, and alkyd resin. Among these resins, an ethylene-vinyl acetate copolymer and a polyurethane resin emulsion are particularly preferable because they are particularly effective for improving image storability (light resistance, water resistance, and moisture resistance).

(B) At least one water-soluble resin selected from starch and cellulose derivatives The water-soluble resin (B) includes modified starch such as oxidized starch, etherified starch and cationized starch, carboxymethylcellulose, Examples include cellulose derivatives such as ethyl cellulose.

(C) Water-soluble resin other than starch and cellulose derivative The water-soluble resin (C) includes completely or partially saponified PVA, carboxylic acid-modified PVA, and silyl-modified PVA.
Examples of such resins include VA, acetoacetyl group-modified PVA, and polyvinyl acetal resin, which are considered to have good adhesiveness. Among these, partially saponified PVA and carboxylic acid-modified PVA are particularly preferable because of their excellent adhesiveness and image storability.

The mixing ratio of the pigment and the binder resin to be contained in the ink receiving layer can be selected within a range in which the balance of the image recording quality such as the strength of the ink receiving layer, the strength of the gloss adjusting layer and the ink absorbency is maintained. it can. Specifically, pigment: binder resin = 3: 7-1: 1, emulsion resin (A): water-soluble resin (total amount of resin (B) and resin (C)) = 2: 3-4: 1. Pigment: binder resin = 4: 6-1: 1, emulsion resin (A): water-soluble resin (total amount of resin (B) and resin (C)) = 3: 2
~ 4: 1 is more preferred. If the amount of the pigment is too large, the ink receiving layer may be broken in the production due to insufficient adhesive strength of the binder resin, or the gloss adjusting layer laminated thereover may be broken. Conversely, if the amount of the binder resin is too large, the air permeability increases, which causes deterioration in image recording quality such as ink absorbency.

The mixing ratio of the above resins (A), (B) and (C) constituting the binder resin is 100 parts by weight of the emulsion resin (A) and 10 parts by weight of the water-soluble resin (B).
７５75 parts by weight, water-soluble resin (C): 15-75 parts by weight. Further, the emulsion resin (A): 20.0 to 35.0% by weight, the water-soluble resin (B): 3.0 to 15.0% by weight, the water-soluble resin, based on the whole material constituting the ink receiving layer. (C):
5.0 to 15.0% by weight is preferred. If any one of these three components is lacking, the film-forming properties of the ink-receiving layer are improved, the air permeability is increased, and the image recording quality such as ink absorbency is reduced, thereby achieving the object of the present invention. It will be difficult.

The air permeability of the ink receiving layer is determined according to “J. TAPPI Paper Pulp Test Method No. 5” in order to maintain the air permeability of the ink jet recording medium after applying the glossiness adjusting layer within a certain level. The value in the specified Oken type air permeability test method, preferably 10 to 300 seconds, more preferably 10 to 300 seconds
It is 200 seconds, and more preferably 10 to 100 seconds. If the air permeability of the ink receiving layer exceeds 300 seconds, it may cause deterioration in image recording quality such as a decrease in ink absorbency. Therefore, the air permeability of the ink receiving layer needs to be within the above range.

Other Additives In the ink receiving layer, other additives such as a light fastness improving agent, a dye / pigment fixing agent, a pigment dispersant, a thickener, a flow improver, an antifoaming agent, and a foam inhibitor Agent, release agent, foaming agent, penetrant,
Coloring dyes, coloring pigments, optical brighteners, preservatives, water resistance agents,
A hardener and the like can be appropriately compounded as needed.

Here, an additive which has an effect of preventing photo-fading of an image by being added to the ink receiving layer is defined as the above-mentioned chemical for improving light resistance. Examples of the agent for improving light resistance include divalent or higher valent water-soluble metal salts, ultraviolet absorbers, antioxidants and the like. Further, as the dye fixing agent,
A cationic dye fixing agent is preferably used. Examples of the cationic dye fixing agent include polyamine resin-based materials and quaternary ammonium salt resin-based materials. A synergistic effect is considered between the lightfastness improving agent and the cationic dye fixing agent. Therefore, in order to further improve image recording quality, the ink receiving layer is preferably provided with a lightfastness improving agent: a cationic dye fixing agent, preferably in a ratio of 4: 1-1: 1, more preferably in a ratio of 3: 2-1: 3. And a pigment + binder resin: another additive, preferably 1
The solid content ratio is preferably 9: 1 to 4: 1, more preferably 9: 1 to 4: 1.

Further, as the above-mentioned ultraviolet absorber and antioxidant, a polycarboxylic acid and a functional part (an ultraviolet absorbing part,
Liquid type with esterification of the antioxidant function),
A dispersion type dispersed with a surfactant is preferred.

The ink receiving layer in the ink jet recording medium of the present invention is composed mainly of the above-mentioned pigment and binder resin, and if necessary, other additives are added to form a coating liquid on the support. And laminated. From the viewpoint of satisfying various conditions such as sufficient image recording quality and adhesion to a support and avoidance of production problems such as powder dropping during cutting, the solid content ratio of these materials is preferably a pigment. : 40.0 to 60.0% by weight, binder resin: 20.0 to 40.0% by weight, and other additives: 1.0 to 40.0% by weight.

(3) Glossiness Adjusting Layer The ink jet recording medium of the present invention is obtained by coating an ink receiving layer on both sides of a support and laminating a glossiness adjusting layer on the ink receiving layer. The gloss adjusting layer preferably has a characteristic of a gloss of 40 or more according to a 60-degree specular gloss test method. The glossiness adjusting layer is laminated by using a mixed material of a pigment and a binder resin as a coating fluid for the glossiness adjusting layer, and applying this to the surface of the ink receiving layer.

It is essential that the binder resin of the gloss adjusting layer used in the present invention is weakly cationic or anionic, and examples of the anionic one include carboxyl group-modified PVA, sulfate group-modified PVA, and sulfone group-modified PVA. Modified PVAs, such as acid group-modified PVA and phosphate group-modified PVA, may be mentioned. Examples of weakly cationic ones include primary to primary compounds such as acrylamide, monoalkylaminoalkyl (meth) acrylate, diallylamine, and dialkylaminoalkyl (meth) acrylate.
Examples include polymers such as tertiary amines and copolymers thereof. Among them, copolymers of these monomers with acrylic acid esters such as 2-hydroxyethyl (meth) acrylate or dialkoxypolyalkylene glycol (meth) acrylate and acrylonitrile are preferred.

The weak cationic property in the present invention has a property that it can be easily converted to a state close to nonionicity by setting it in an alkaline atmosphere and can be stably present with colloidal silica gel or the like.
Specifically, as described above, those not quaternary aminated with inorganic acids (such as hydrochloric acid) (not in a strongly acidic atmosphere) correspond to this.

As described above, in the present invention, by using a binder resin having the above-mentioned properties as the binder resin for the glossiness adjusting layer, it is possible to prevent agglomeration occurring during the preparation of the coating solution for the glossiness adjusting layer and to prevent the aggregation of the coating solution. Stability can be improved. Further, by utilizing the property that the coating liquid is weakly cationic or anionic, it suppresses penetration and penetration into the ink receiving layer, and improves the adhesiveness of the glossiness adjusting layer to the ink receiving layer, thereby improving ink adhesion. Breakage and peeling at the interface between the receiving layer and the glossiness adjusting layer can be prevented.

As the pigment contained in the glossiness adjusting layer, anionic colloidal silica in which ultrafine particles of silicic anhydride (silica) are stably dispersed in water is particularly preferable.

Further, the glossiness adjusting layer of the present invention can adjust the glossiness according to the kind of the pigment and the binder resin and the mixing ratio of the pigments. It can be different.

The mixing ratio of the pigment and the binder resin in the glossiness adjusting layer is preferably such that the binder resin is contained in the pigment in an amount of 5.0 to 50.0% by weight from the viewpoint of sufficiently maintaining the gloss. More preferably, the amount is 0.0 to 30.0% by weight. The coating amount at which the glossiness adjusting layer exhibits good glossiness without impairing the function as the ink passage layer is preferably 3 to 25 g / m ² , and 5 to 15 g / m ^2.
g / m ² is more preferable.

(4) Method of Laminating Ink Receiving Layer and Glossiness Adjusting Layer Next, a method of laminating the ink receiving layer and the glossiness adjusting layer on both surfaces of the support will be described. The above-mentioned materials constituting the ink receiving layer are prepared in an appropriate mixing ratio, and are dissolved or dispersed in a suitable solvent such as water or alcohol to prepare a coating liquid for the ink receiving layer. This coating liquid is applied on a support by using a coating machine such as a blade coater, a roll coater, an air knife coater, a bar coater, a rod blade coater, and a size press on or off as appropriate. The coating amount of the coating liquid, for example, preferably 5 to 30 g / ^{m 2} in one layer type, more preferably if 5 to 20 g / ^{m 2.} When a first ink receiving layer is laminated on a support and a second ink receiving layer is laminated thereon to form a two-layer type,
The coating amount of the first ink receiving layer is preferably ^{5~30g / m 2, 5~20g / m} 2 is more preferable. Further, the coating amount of the second ink receiving layer is preferably 5 to 15 g / m ² ,
10 g / m ² is more preferred. If the amount is less than the above range, sufficient ink absorbency and fixability may not be obtained. On the other hand, if the amount is too large, problems such as powder dropout may occur, leading to a decrease in productivity and an increase in cost.
In particular, when the coating amount of the second ink receiving layer exceeds 15 g / m ² , it becomes difficult for the ink to pass through the second ink receiving layer, and bleeding may occur, and the image clarity may be impaired. . As described above, it is preferable to control the amount of the ink receiving layer coating liquid applied according to the number of the ink receiving layers to be laminated. After application, machine calendar, T
The finishing may be performed using a calendar such as a G calendar, a super calendar, or a soft calendar.

The air permeability at the stage of applying the ink receiving layer coating solution on the support and coating the ink receiving layer (before the gloss adjusting layer is laminated) is determined by the permeability of the ink receiving layer. Since the porosity is 10 to 300 seconds, the air permeability of the support substantially applies. That is, the air permeability is “J. TA
PPI Paper Pulp Test Method No. 5 "in the Oken type air permeability test method defined in 5", preferably 10 to 1000
Seconds, more preferably 10 to 400 seconds, and 10 to 10 seconds.
0 seconds is more preferable. If the air permeability exceeds 1000 seconds, the air permeability of the final product will not be less than this, which may cause a decrease in image recording quality such as a decrease in ink absorbency, and Also, the coating of the glossiness adjusting layer is not preferable because the strength at the interface between the glossiness adjusting layer and the ink receiving layer is reduced, and peeling or layer destruction may occur.

Next, as a method of laminating the glossiness adjusting layer on the ink receiving layer, for example, a generally known mirror surface drum casting method can be mentioned. However, in manufacturing the ink jet recording medium of the present invention, a coating liquid layer is formed by applying a coating liquid for a glossiness adjusting layer on an ink receiving layer laminated on a support. A film (for example, a polyolefin resin film, a tetrafluoroethylene resin film, a releasable siliconized resin film, etc.) having a smooth surface and selected according to the glossiness adjustment layer to be coated is overlaid and adhered on the layer. A film casting method in which the film is peeled off after the coating liquid layer is dried and the film is peeled off is more preferable.

The lamination of the glossiness adjusting layer on the ink receiving layer can be carried out simultaneously with the coating process of the ink receiving layer and on-machine without the coating condition of the glossiness adjusting layer being deteriorated. No accompanying deterioration in image recording quality such as ink absorbency is observed. Further, if the lamination of the glossiness adjustment layer is performed by an off-machine, adjustment of the air permeability of the medium and the like becomes easier,
It is possible to more closely control the image recording quality.

[0039]

EXAMPLES Next, examples and comparative examples based on the present invention will be shown to further clarify the effects of the present invention. In each of Examples and Comparative Examples, the basis weight was 160 g / m ² , and the air permeability was 50.
A high-quality paper as a support is used as a support, and an ink receiving layer is formed by sequentially applying and drying a coating solution in which a material having the following composition is dissolved and dispersed in water on both sides of the support, and a glossiness adjusting layer is further laminated thereon. Thus, an ink jet recording medium was obtained. Listed in the examples are percentages of dry solids weight. The coating amount was 10 g / m ² for both the ink receiving layer and the glossiness adjusting layer unless otherwise specified.

Example 1 A coating solution for an ink receiving layer having the following composition was applied to both surfaces of a support by a bar coater method and dried (at 120 ° C. for 3 minutes). The coating liquid for an adjustment layer was applied by a film casting method and dried to prepare a double-sided inkjet recording medium of Example 1 in which an ink receiving layer and a glossiness adjustment layer were applied to both surfaces of a support. The glossiness of the surface was 52.9.
(60 ° specular gloss). [Ink receiving layer] Binder resin Emulsion resin (A): Ethylene-vinyl acetate emulsion (Kuraray: Panflex OM-5500) 20.4% by weight Water-soluble resin (B): Cationized starch (Daiwa Chemical Co., Ltd.) 6.0% by weight of water-soluble resin (C): 13.6% by weight of partially saponified PVA (Kuraray Co., Ltd .: Kuraray Poval PVA420) ・ White pigment silica gel (Mizukasil P- 78D) 40.0% by weight-Cationic dye fixing agent Polyamine-based dye fixing agent (Sumitomo Chemical Co., Ltd .: Sumireze Resin 784S) 10.0% by weight-Light fastness improving agent (Tomita Pharmaceutical Co., Ltd .: Magnesium chloride S) ) 10.0% by weight

[Glossiness Adjusting Layer] Binder Resin Acrylic Resin Copolymer (Weak Cationic) N, N-Dimethylaminoethyl Methacrylate Homopolymer (Adjusted to Alkaline and Inhibited Quaternization) 10.0 Weight% ・ White pigment colloidal silica (Nissan Chemical Industries: Snowtex UP) 45.0% by weight (Nissan Chemical Industries: Snowtex XL) 45.0% by weight

<Example 2> The same ink receiving layer as in Example 1 was laminated except that the coating liquid for the gloss adjusting layer had the following composition. A double-sided inkjet recording medium of Example 2 coated with an adjustment layer was produced. The glossiness of the surface is 56.
It was 6. [Glossiness adjusting layer]-Binder resin Maleic acid-modified PVA (anionic) (Nippon Gohsei Chemical Co., Ltd .: Gosenal T-350) 10.0% by weight-White pigment colloidal silica (Nissan Chemical Industries: Snowtex UP) 45.0% by weight (Nissan Chemical Industries: Snowtex XL) 45.0% by weight

Example 3 The same gloss adjusting layer as in Example 2 was laminated except that the coating liquid for the ink receiving layer had the following composition, whereby the ink receiving layer and the gloss were formed on both surfaces of the support. The double-sided inkjet recording medium of Example 3 coated with the adjustment layer was produced. The glossiness of the surface is 55.
It was 3. [Ink receiving layer]-Binder resin Itaconic acid-modified PVA (Kuraray Co., Ltd .: Kuraray Poval KL-318K) 39.0% by weight-White pigment silica gel (Mizukasil P-78D) 39.0% by weight-Cation Fixable agent for dyes Polyamine-based dye fixing agent (Sumitomo Chemical Co., Ltd .: Sumireze Resin 784S) 11.0% by weight-Lightfastness improving agent Divalent or higher valent water-soluble metal salt (Tomita Pharmaceutical: Magnesium chloride S) 11.0% by weight

Comparative Example 1 The same ink receiving layer as in Example 1 was laminated except that the coating liquid for the gloss adjusting layer had the following composition, whereby the ink receiving layer and the gloss were formed on both sides of the support. A double-sided inkjet recording medium of Comparative Example 1 coated with an adjustment layer was produced. The glossiness of the surface is 58.
It was 7. [Glossiness adjusting layer]-Binder resin cationically modified PVA (cationic) (manufactured by Nippon Synthetic Chemical Industry: Gosefimer K-210) 10.0% by weight-White pigment colloidal silica (manufactured by Nissan Chemical Industries: Snowtex) UP) 45.0% by weight (Nissan Chemical Industries: Snowtex XL) 45.0% by weight

Comparative Example 2 The same ink receiving layer as in Example 1 was laminated except that the coating liquid for the gloss adjusting layer had the following composition, whereby the ink receiving layer and the gloss were formed on both sides of the support. A double-sided inkjet recording medium of Comparative Example 2 coated with an adjustment layer was produced. The glossiness of the surface is 57.
It was 7. [Glossiness adjusting layer]-Binder resin Fully saponified PVA (nonionic) (Kuraray: Kuraray Poval PVA-117) 10.0% by weight-White pigment colloidal silica (Nissan Chemical Industries: Snowtex UP) 45 4.0% by weight (Nissan Chemical Industries, Ltd .: Snowtex XL) 45.0% by weight

Comparative Example 3 The same ink receiving layer as in Example 3 was laminated except that the coating liquid for the glossiness adjusting layer had the following composition, whereby the ink receiving layer and the glossiness were formed on both sides of the support. A double-sided inkjet recording medium of Comparative Example 3 coated with an adjustment layer was produced. The glossiness of the surface is 54.
It was 2. [Glossiness adjusting layer]-Binder resin Fully saponified PVA (nonionic) (Kuraray: Kuraray Poval PVA-117) 10.0% by weight-White pigment colloidal silica (Nissan Chemical Industries: Snowtex UP) 45 4.0% by weight (Nissan Chemical Industries, Ltd .: Snowtex XL) 45.0% by weight

For the double-sided ink jet recording media of Examples 1 to 3 and Comparative Examples 1 to 3, a commercially available ink jet printer (PM-750, manufactured by Seiko Epson Corporation) was used.
The following evaluation test was performed using C).

(1) Print Density A color patch is printed on one side of an ink jet recording medium, and a spectrophotometer (GRETAG, manufactured by Gretag Macbeth: GRETAG) is used.
Using SPM50), the reflection density of each color of Bk (black), C (cyan), M (magenta), and Y (yellow) was measured to evaluate the image print density characteristics. (Evaluation results show that the same image quality was obtained on both sides of each sample, and Table 1 shows only the measurement data on the front side.)

(2) Image clarity A color patch is printed on one side of an ink jet recording medium, and a spectrophotometer (GRETAG Macbeth: Gretag) is used.
SPM50), the saturation of each color of C (cyan), M (magenta), and Y (yellow): C = (a ² +
b ² ) ^1/2 was measured and evaluated. (Evaluation results show that the same image quality was obtained on both sides of each sample, and Table 1 shows only the measurement data on the front side.)

(3) Cockling Black solid printing with an optical density of 1.0 was performed on both sides of the ink jet recording medium, and the degree of cockling (wavy) on the printed surface was visually evaluated as follows. A: Cockling is not recognized at all. B: Cockling is slightly recognized, but is not a problem in practical use. C: Cockling is clearly recognized, and there is a practical problem.

(4) Offset A color patch is printed on one side of the ink jet recording medium, and immediately thereafter, the printing surface of the other recording medium is pressed from above, so that the offset of the undried portion is visually observed. Was evaluated as follows. A: No set-off is recognized at all. B: To the extent that it cannot be determined without enlargement, there is no practical problem. C: Set-off can be determined by appearance and there is a practical problem.

(5) Image Intensity Black solid printing with an optical density of 1.0 was performed on one side of the ink jet recording medium, and the printed matter was passed through a printer again to perform similar printing on the other side. . At this time, the jaggedness caused by the lack of the recorded image on the printed surface by the conveying roller was visually evaluated as follows. A: No omission is recognized at all. B: Although there is a slight dent, there is no practical problem without image deterioration being observed. C: A part of the recorded image is missing and there is a practical problem.

(6) Air Permeability Measurement The air permeability of the ink jet recording medium (unrecorded product) is measured by the Oken type air permeability test method specified in “J. TAPPI Paper Pulp Test Method No. 5”. did.

(7) Light fastness Light fastness 1 (residual density) For a print sample of a color patch similar to the above (4), a xenon weatherometer (manufactured by ATLAS: Ci-
5000), a black panel temperature of 63 ° C., a relative humidity of 50% and an ultraviolet irradiation intensity of 340 nm of 0.35 W / m ^2.
An exposure test of 30 kJ / m ² was performed under the following conditions. Next, a spectrophotometer (GRETAG, manufactured by Gretag Macbeth)
The reflection density of M (magenta) was measured using SPM50), and the light resistance corresponding to the residual density was evaluated as follows. A: The concentration after exposure exceeds 90% before exposure B: The concentration after exposure is 80 to 90% before exposure C: The concentration after exposure is less than 80% before exposure

Light resistance 2 (light yellowing) Xenon weatherometer (manufactured by ATLAS: Ci-50)
00), a black panel temperature of 63 ° C. and a relative humidity of 5
An exposure test of 30 kJ / m ² was performed on the inkjet recording medium (unrecorded product) under the condition of 0%, 340 nm ultraviolet irradiation intensity 0.35 W / m ² . Then, a spectrophotometer (GRETAG SPM manufactured by Gretag Macbeth)
50), the color difference before and after exposure obtained from the values of L ^* , a ^* , and b ^* of the ink jet recording medium itself measured by using ΔE is defined as ΔE. Was evaluated as follows. A: The value of ΔE is less than 5 B: The value of ΔE is 5 to 10 C: The value of ΔE exceeds 10

Light fastness 3 (residual density) A print sample of a Y (yellow), M (magenta), C (cyan), Bk (black) color patch is left for about one month through a south-facing glass window. After that, the average value of the concentration residual ratio was measured and evaluated as follows. A: Density after standing exceeds 90% before leaving B: Density after leaving 80 to 90% before leaving C: Density after leaving less than 80% before leaving

Light resistance 4 R (red), G (green), through south-facing glass window
The print sample of the B (blue) color patch was left for about one month. Next, the L measured using a spectrophotometer (GRETAG SPM50 manufactured by Gretag Macbeth) was measured.
The color difference before and after standing obtained from the values of ^* , a ^* , and b ^* was defined as ΔE, and the average value of ΔE for each of R, G, and B was evaluated as follows. A: Average value of ΔE is less than 5 B: Average value of ΔE is 5 to 10 C: Average value of ΔE exceeds 10

(8) Room preservation A print sample (portrait image) of an ink jet recording medium is placed on an office wall about 2 m away from a north facing window.
Was stuck and left for 6 months, and then the indoor storage stability was visually evaluated as follows. A: No change in color compared to the initial stage B: Change in color compared to the initial stage

(9) Preservation of Clear File An inkjet recording medium (unrecorded product) was stored in a clear file (CL-A420) manufactured by Mitsubishi Pencil Co., Ltd. so as to protrude by about 2 cm, and stored at 60 ° C. for 2 weeks. Thereafter, the degree of yellowing is determined by the color difference ΔE (CIE L ^* a ^*)
b ^* ) was evaluated as follows. A: ΔE is less than 2 B: ΔE is 2 to 5 C: ΔE exceeds 5

(10) Ink Absorption The degree of bleeding of a mixed color and a single color in an ink-jet printer was compared with that of genuine glossy paper (manufactured by Seiko Epson Co., Ltd .: glossy paper (thick mouth) photo paper for Super Fine). And visually evaluated as follows. The difference between the SCID images is high-definition color digital standard image data, and is defined as ISO / JIS-SCID (JIS X
9201-1995) in comparison with N1: portrait image or N3: fruit basket image. A: equal to or more than genuine glossy paper, no problem at all B: slightly inferior to genuine glossy paper, but the difference in the SCID image is insignificant and excellent without practical problems C: the difference in the SCID image Recognized and practically inferior

(11) Image water resistance Y (yellow), M (magenta), C (cyan), R
(Red), G (Green), B (Blue), Bk (Black) A drop of water was attached to the printed portion of the sample on which the characters were printed, and the state after air-drying was as follows. Was evaluated. A: No dye outflow B: Dye outflow, but legible C: Not legible

(12) Image moisture resistance Y (yellow), M (magenta), C (cyan), R
(Red), G (Green), B (Blue), Bk (Black) samples printed with color patches at 40 ° C.
The film was exposed to a high-humidity condition of 85% for three days and nights, and the moisture resistance of the image was evaluated as follows from the deepening of the color patch and the degree of blurring of the outline. A: No darkening and no contour bleeding B: Slight bleeding, but excellent without practical problems C: Poor in practical use

(13) Water Resistance of Ink Receiving Layer In each of Examples and Comparative Examples, a sample was prepared in which only an ink receiving layer was formed on both surfaces before the glossiness adjusting layer was provided. With respect to the sample on which the color patch was printed, 5 mL of water was dropped on the ink receiving layer, and the ink receiving layer was examined for breakage or peeling caused by rubbing on the ink, and evaluated as follows. A: No breakage or peeling of the ink receiving layer is observed at all. B: Peeling of the ink receiving layer is slightly observed, but the image is retained and is excellent without practical problems. C: The ink receiving layer is broken. Peeled off, causing practical problems

(14) Water Resistance of Glossiness Adjusting Layer 5 mL of water is dropped on the glossiness adjusting layer, and breakage or peeling of the glossiness adjusting layer caused by rubbing thereon is examined, and evaluated as follows. . A: No breakage or peeling of the glossiness adjusting layer was observed at all. B: Peeling of the glossiness adjusting layer was slightly observed, but it was excellent without practical problems. C: The glossiness adjusting layer was broken and peeled off at the root. Has practical problems

(15) Adhesiveness of Glossiness Adjusting Layer The surface condition of the glossiness adjusting layer of the ink jet recording medium (unrecorded product) was visually observed to evaluate the adhesiveness. A: No peeling or the like of the glossiness adjusting layer is observed at all. B: Although slight peeling or chipping is observed, it is within an allowable range and has no practical problem and is excellent. C: Countless peeling or chipping is observed. Table 1 shows the results of the above-mentioned tests and the measurement results, which have practical problems.

[0066]

[Table 1]

According to Table 1, the evaluations of the double-sided ink jet recording media of Examples 1 and 2 all show a high level of A, and the image recording quality (cockling, light resistance, moisture resistance, water resistance, etc.) is double-sided. It was confirmed that not only is it excellent as a recording medium, but also excellent in productivity at the time of applying a glossiness adjusting layer. In Example 3 in which a conventional binder resin was used for the ink-receiving layer, the evaluation in terms of cockling, image strength, air permeability, ink absorptivity, and adhesiveness of the gloss adjusting layer was slightly inferior. There was no problem. On the other hand, the double-sided inkjet recording medium of the comparative example was inferior in the adhesiveness of the glossiness adjusting layer, and had a problem in productivity. As a result, the double-sided inkjet recording medium of the present invention proved to be extremely promising as a double-sided inkjet recording medium because it has excellent image recording quality as well as excellent productivity. Was done.

[0068]

As described above, according to the present invention, it is essential that the binder resin of the glossiness adjusting layer is anionic or weakly cationic. In a more preferred embodiment, the binder resin in the ink receiving layer is used. Contains three components: an emulsion resin (A), at least one water-soluble resin (B) selected from starch and a cellulose derivative, and a water-soluble resin (C) other than starch and a cellulose derivative. Not only the recording quality is excellent, but also the productivity of the excellent glossiness adjusting layer is achieved. Therefore, it is very promising as an inkjet recording medium for double-sided recording, and has an effect that it can be sufficiently applied to full-color high-speed printing in the future.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuhiro Kubota 3-1 Yosoba Tomoecho, Shizuoka City, Shizuoka Prefecture Inside the Paper Division of Hamakawa Paper Mill Co., Ltd. (72) Inventor Takeshi Yoshimoto 3 Yoyo Tomoecho, Shizuoka City, Shizuoka Prefecture No. 1 In the Paper Division of Hamakawa Paper Mills Co., Ltd. (72) Inventor Shigeru Asai No. 3 in Yoyoha-cho, Shizuoka City, Shizuoka Prefecture Inside of the Paper Division of Hamakawa Paper Mills Co., Ltd. (72) Minoru Tsuchida Shizuoka City, Shizuoka Prefecture No. 3-1 Yomobacho, Paper Business Division, Hamakawa Paper Mills Co., Ltd. (72) Inventor Kiyoshi Iwamoto No. 3-1 Yomoe Tomoecho, Shizuoka-shi, Shizuoka Prefecture, Paper Business Division of Hamakawa Paper Mill Co., Ltd. (72) Hiroyuki Onishi, Inventor 3-5-5 Yamato, Suwa City, Nagano Prefecture Seiko Epson Corporation (72) Inventor Jun Sugiyama 3-5-5 Yamato Suwa City, Nagano Prefecture Seiko Epson Shares In-house F-term (reference) 2C056 EA13 FC06 2H086 BA16 BA24 BA33 BA34 BA41 4L055 AG18 AG46 AG47 AG48 AG59 AG64 AG70 AG71 AG94 AG97 AH02 AH37 AH50 AJ04 BE09 EA12 EA32 FA13 FA15 FA22 GA09

Claims (5)

[Claims] 1. An ink jet recording medium comprising an ink receiving layer containing a pigment and a binder resin on both surfaces of a support, and a glossiness adjusting layer formed on the ink receiving layer. The double-sided inkjet recording medium, wherein the binder resin contains a weak cationic or anionic resin. 2. The binder resin of the ink receiving layer,
An emulsion resin (A), at least one water-soluble resin (B) selected from starch and a cellulose derivative,
2. The double-sided ink jet recording medium according to claim 1, comprising three components of a water-soluble resin (C) other than starch and a cellulose derivative. 3. The binder resin of the ink receiving layer,
The water-soluble resin (B) is contained in a proportion of 10 to 75 parts by weight and the water-soluble resin (C) is contained in a proportion of 15 to 75 parts by weight with respect to 100 parts by weight of the emulsion resin (A). The double-sided ink jet recording medium according to claim 2. 4. The emulsion resin (A) is used in an amount of 20.0 to 3 with respect to the whole material constituting the ink receiving layer.
5.0% by weight, the water-soluble resin (B) is 3.0 to 15.
4. The double-sided inkjet recording medium according to claim 2, wherein the water-soluble resin (C) is contained at a ratio of 5.0 to 15.0% by weight. 5. The double-sided ink jet recording medium has an air permeability of 10 to 1000 seconds.
5. The double-sided ink jet recording medium according to any one of items 1 to 4.