JP2002347328A - Ink jet recording medium - Google Patents

Abstract

(57) Abstract: An ink jet recording medium for recording using ink, and particularly relates to an ink jet recording medium capable of clear printing with little blur of characters and color boundaries. In an ink jet recording medium provided with an ink receiving layer containing a pigment and an adhesive on at least one surface of a support, the surface of the ink receiving layer has a surface tension of 40 dy.
The contact angle after 0.1 second measured using a ne / cm liquid is 50 to 80 degrees, and 5 μl of a liquid having a surface tension of 40 dyne / cm is collected with a syringe, and the liquid dropped on the ink receiving layer is an ink. An ink jet recording medium characterized in that the time for absorption in the receiving layer is 60 seconds or less.

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 for recording using ink, and more particularly, to an ink jet recording medium capable of clearly printing characters and blurring of color boundaries.

[0002]

2. Description of the Related Art Ink-jet recording systems have been widely used as recording apparatuses for various graphics and color images, including characters, because of low noise during recording, easy colorization, and high-speed recording. It is rapidly spreading in applications. Depending on the application, more advanced recording characteristics have been required, for example, when used for slips, the spread of ink dots during recording is small,
It is particularly required that the bleeding be small.

[0003] For example, Japanese Patent Application Laid-Open No. 9-99633 discloses a self-emulsifying cationic polymer comprising a water-insoluble acrylic copolymer in an ink jet recording medium having an ink receiving layer containing a pigment and an adhesive. It is disclosed that by containing a resin, the ink can be absorbed at a high speed, the spread and bleeding of the ink are small, and recording can be performed at a high speed. However, even with this recording medium, there is a problem that the blur of characters and the blur of color boundaries are not sufficient.

Japanese Patent Application Laid-Open No. 8-2766653 specifies polyvinyl alcohol as an adhesive in a receiving layer mainly composed of a highly absorbent pigment and an adhesive on one side of a base paper containing a filler and an internal sizing agent. Or by including a sizing agent, by defining the contact angle of the ink receiving layer measured using a liquid having a surface tension of 40 dyne / cm to 85 to 100 degrees, the bleeding of characters and ruled lines is reduced, and It is disclosed that recording with excellent printability (ink absorption, image density) by a color inkjet printer can be performed. However, this recording medium has a problem that ink absorption is slow and color bleeding is poor.

[0005]

The present invention relates to an ink-jet recording medium for recording using ink, and more particularly to an ink-jet recording medium that can print clearly with little blurring of characters and color boundaries.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted various studies to solve the above-mentioned problems, and as a result, have found that it can be achieved by forming an ink receiving layer satisfying specific physical properties. . According to the present invention, in an ink jet recording medium provided with an ink receiving layer containing a pigment and an adhesive on at least one side of a support, the surface of the ink receiving layer was measured using a liquid having a surface tension of 40 dyne / cm. The contact angle after one second is 50 to 80 degrees, and the surface tension is 4
An ink jet recording medium characterized in that 5 μl of a 0 dyne / cm liquid is collected with a syringe, and the time for which the liquid dropped on the ink receiving layer is absorbed by the ink receiving layer is 60 seconds or less. Further, the ink receiving layer preferably contains a water-repellent substance. As the water-repellent substance, use of a silicone resin or a fluorine resin is more preferable.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, the surface of the ink receiving layer has a contact angle of 0.1 to 2 after 0.1 second of the receiving layer measured using a liquid having a surface tension of 40 dyne / cm. Need to be. By the way, if the contact angle is less than 50 degrees, characters and ruled lines are blurred, the lines become thicker, and color boundary blurs are increased. If it exceeds 80 degrees, the ink absorbency becomes slow, and stains occur during high-speed printing. Preferred contact angles are between 60 and 80 degrees.

Further, a surface tension of 40 is applied to the surface of the ink receiving layer.
Using a dyne / cm solution, 5 μl is collected with a 5 to 10 μl collection syringe, and the time during which the liquid dropped on the receiving layer is absorbed by the receiving layer is set to 60 seconds or less. By the way, if the absorption time exceeds 60 seconds, the ink may strike the recording paper holding plate of the printer or the like while the ink is present on the surface of the receiving layer, causing stains during recording. A more preferred absorption time is 55 seconds or less.

As the ink receiving layer having the above-mentioned physical properties, for example, a water repellent substance may be blended in the ink receiving layer or on the surface of the ink receiving layer to adjust both physical properties. As the water-repellent material, a neutral sizing agent such as AKD or ASA can be used in addition to a water-repellent such as a fluorine-based resin and a silicone-based resin. These water-repellent substances can be used alone or in combination of two or more. When blending a water-repellent substance with the ink receiving layer, the amount of the compound depends on the type of the water-repellent substance used, the type of the pigment or the adhesive constituting the ink receiving layer,
Since the amount varies depending on the type of the support and the type of the support, it cannot be said unconditionally. If the amount of the water-repellent substance is excessive, the contact angle increases,
In addition, since the time for the ink to be absorbed by the ink receiving layer exceeds 60 seconds, stains occur during recording. If the amount of the water-repellent substance is too small, the contact angle becomes small, and the color boundary bleeding becomes large.

[0010] The ink receiving layer according to the present invention contains a pigment and an adhesive as main components. The pigment preferably contains a pigment that is porous, has high ink absorbency, and enables clear color development. Examples of such pigments include fine particle synthetic silica, zeolite, calcium carbonate, calcium silicate, aluminum hydroxide, alumina, calcined clay, kaolin, clay, talc, white carbon, organic pigments (plastic pigments), and generally paper coating. Examples of the pigment used are exemplified, and it is particularly preferable to use fine-particle synthetic silica.

The proportion of the pigment used is not limited, but is 50 to 90% by weight of the solid content of the receiving layer. If it is less than 50%, the ink absorbency becomes insufficient, and if it exceeds 90%, the strength of the ink receiving layer may be reduced.

The adhesive used in the ink receiving layer of the present invention includes polyvinyl alcohol and its derivatives, proteins such as polyvinylpyrrolidone and casein, starch and its derivatives, styrene-butadiene copolymer, acrylate and methacrylate. Water-insoluble acrylic polymer latex such as a polymer or a copolymer, ethylene-vinyl acetate copolymer, a vinyl polymer latex such as an ethylene-vinyl chloride copolymer, or a carboxyl group of these various polymers, Modified polymer latex containing functional groups such as cationic groups, synthetic resin-based aqueous adhesives such as melamine resin and urea resin, maleic anhydride copolymer resin, polyacrylamide, polymethyl methacrylate, polyurethane resin, Saturated polyester resin system,
Polyvinyl butyral, a polymer such as a synthetic resin adhesive such as an alkyd resin, has good adhesion to a pigment or a base material, and has good affinity with an aqueous ink, so that it improves the liquid absorbing property. It is preferably used. Above all, polyvinyl alcohol and its derivatives, and water-insoluble acrylic copolymers are preferable because they have strong adhesive strength and have an appropriate ink absorbency.

The proportion of the adhesive used in the ink receiving layer is about 10 to 50% by weight, preferably 10 to 40% by weight of the solid content of the receiving layer. If it is less than 10%, the adhesive strength becomes insufficient, and there is a concern that the strength of the receiving layer may decrease. 5
If it exceeds 0%, the adhesive strength is increased, but the use ratio of the pigment is reduced, and a problem may occur in the ink absorbency as described above.

In order to improve the water resistance of a printed image with an aqueous ink, a polydiallyldimethylammonium resin, a polyethyleneimine resin, a polyamine resin, a polyamide resin, a polyamide epichlorohydrin resin, a polyamine epichlorohydrin resin, Cationic polymer compounds such as polyamide polyamine epichlorohydrin resin, polydiallylamine resin, and dicyandiamide condensate can be suitably used.

Further, if necessary, a pigment dispersant, a thickener, an antifoaming agent, a foam inhibitor, a foaming agent, a release agent, a penetrating agent, a wetting agent, a thermal gelling agent, a lubricant, and others in the technical field. Various known auxiliaries can be used.

The ink receiving layer is formed on a support by a commonly used coating means such as a size press, a gate roll, a shim sizer, a roll coater, a bar coater, an air knife coater, a rod blade coater, a blade coater, a die coater, and a curtain coater. , A dry weight of about 1.0 to 10 g / m ² , preferably 2.0 to 7.0 g / m ² .
It is formed with a coating amount of about 0 g / m ² . 1.0 coating amount
If it is less than g / m ² , the ink absorption capacity is small, and
If it exceeds 0 g / m ² , it will look like coated paper.

As the support, it is preferable to use an ink-absorbing paper support. Typical pulp components used as a paper support include chemical pulp such as softwood bleached kraft pulp and hardwood bleached kraft pulp, mechanical pulp such as GP, B-CTMP, MP, and pulp obtained from non-wood raw materials such as kenaf. Pulp for papermaking, which can be used in combination. Although the material type is not particularly limited, a high blend of softwood (N material) may induce feathering (a phenomenon in which ink bleeds down along the pulp fiber). )) Is preferably not more than 60% of the total pulp component.

It is also possible to use waste paper pulp as the pulp. The raw material of the waste paper pulp is not particularly limited, and may be used newspaper, used printing paper, used corrugated cardboard,
Arbitrary waste paper such as wrapping paper, office waste paper and the like can be used. The method for obtaining recycled pulp from waste paper is not particularly limited, but in general, a defibration step of defibrating waste paper to obtain a pulp suspension, a rough selection for separating foreign substances in the pulp suspension, and a fine selection The recycled pulping is performed through a process, a deinking process for separating printing ink, and a bleaching process for whitening the color. In addition, waste paper that has not been subjected to printing, etc. as a raw material,
It is also possible to use disintegrated pulp that does not require a deinking process.

Freeness of pulp is 200-550ml
Is preferable, and 400 to 500 ml is particularly preferable. If the freeness exceeds 550 ml, the uniformity of the paper may deteriorate, and the uniformity of ink jet recording may be impaired. on the other hand,
If the freeness is less than 200 ml, bleeding may be deteriorated. When pulp in the range of 400 to 500 ml is used, an ink jet recording medium having a good balance between paper uniformity and bleeding can be obtained.

The filler to be internally added is zeolite, silica such as amorphous silica, calcined kaolin, talc, kaolin, calcium carbonate, white carbon, diatomaceous earth, titanium oxide,
At least one selected from inorganic pigments such as activated clay and barium sulfate, and organic pigments such as urea formalin resin, nylon powder and polyethylene powder can be used. Preferably, it is zeolite, silica, calcined kaolin or calcium carbonate. The compounding amount of the filler is 1 to 30% by weight, preferably 5 to 25% by weight based on the whole pulp. If it is less than 1% by weight, bleeding may worsen,
If it exceeds 30% by weight, the print density may be reduced.

As the paper support, polyethylene, polypropylene, ethylene-propylene copolymer, polystyrene,
Polyolefin fibers such as ethylene-vinyl acetate copolymer, halogen-containing polymers such as polyvinyl chloride and polyvinylidene chloride, polyamide fibers such as 6-nylon and 6,6-nylon, polyethylene succinate, polycaprolactone, poly It may contain aliphatic polyester fiber such as lactic acid, polyhydroxybutyrate / valerate copolymer, vinylon fiber and the like.

The paper support can be prepared by an ordinary method using acidic or neutral paper. If necessary, a yield improving agent such as a sulfuric acid band can be used. Further, sizing agents represented by rosin sizing agents, alkenyl succinic anhydrides (ASA), alkyl ketene dimers (AKD), styrene synthetic resins, etc., oxidized starch, enzyme-modified starch, cation-modified starch, esterified starch, Starches such as etherified starch, methylcellulose, ethylcellulose, carboxymethylcellulose, methoxycellulose, hydroxycellulose, fully saponified or partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyvinyl alcohols such as silicon-modified polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, Acrylic amide / acrylic ester copolymer, acrylamide / acrylic ester / methacrylic acid copolymer, styrene / maleic anhydride copolymer alkali salt, isobutyric acid Down-maleic anhydride copolymer alkali salts, water-soluble polymer such as casein, polyvinyl acetate,
Adhesives represented by latex such as polyurethane, polyacrylic acid, polyacrylate, polybutyl methacrylate, styrene / butadiene copolymer, vinyl chloride / vinyl acetate copolymer, styrene / butadiene / acrylic copolymer It may be contained.

The papermaking method is not particularly limited.
Paper is made using a fourdrinier machine, a round net machine, a twin-wire machine, or the like. Degree of Sekihito size of base paper (JIS
P8122) is preferably 5 to 30 seconds. If it is less than 5 seconds, the print density may be insufficient, and if it exceeds 30 seconds, the bleeding may be worsened.

In the present invention, the contact angle is TAPPI st
In accordance with standard T458-84, a wetting index standard solution No. No. manufactured by Wako Pure Chemical Industries, Ltd. was used as a measurement solution. 40 (Surface tension
40 dyne / cm) and DAT1100-FIBR
This is a value obtained by measuring the contact angle of the measurement liquid 0.1 seconds after the dropping using an automatic contact angle measuring device of O System (manufactured by Mabbo).

In the present invention, the absorption time is determined by measuring the wetting index standard solution No. manufactured by Wako Pure Chemical Industries, Ltd. as a measuring solution. Using a 40 (surface tension of 40 dyne / cm), 5 μl was collected with a 5 to 10 μl collection syringe, and the time until the gloss of the measurement liquid dropped on the ink receiving layer due to moisture disappeared was visually measured.

Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples. Parts and% shown in the examples are parts by weight and% by weight unless otherwise specified.

Example 1 Production of paper support 100 parts of L-BKP (freeness: 460 ml), 10 parts of amorphous silica (Tokusil GU-N, manufactured by Tokuyama), 1 part of aluminum sulfate, sizing agent (SPS300, Arakawa) (Manufactured by Kagaku Co., Ltd.) and mixed well to make a papermaking raw material. The paper was made with a fourdrinier multi-cylinder paper machine, and a 2% solution of oxidized starch was applied at 0.8 g / m ² on both sides with a size press and dried. , 70 g / m ²
Was produced. The resulting paper support had a Stekigt sizing degree of 7 seconds.

Manufacture of Inkjet Recording Medium The following ink-receiving layer coating material was applied on one side of the obtained paper support using a bar coater at an absolute dry weight of 7 g / m ² to prepare an inkjet recording medium.

"Paint for ink receiving layer" Silanol-modified polyvinyl alcohol (R-1130, manufactured by Kuraray Co., Ltd.) 48
Parts, amorphous synthetic silica (Fine Seal X-37, manufactured by Tokuyama Corporation) 100 parts, cationic agent (Saftomer ST-3)
300 parts, manufactured by Mitsubishi Chemical Corporation), 10 parts of an acrylic resin (Chuo Rika Bond FK820, manufactured by Chuo Rika) and 0.7 parts of an antifoaming agent (manufactured by San Nopco), and a fluororesin as a water-repellent substance (TG410, manufactured by Daikin Industries, Ltd.) was added in an amount of 5 parts to 100 parts of silica to adjust the solid content to 15%, thereby obtaining an ink-receiving layer paint.

Example 2 Ink-jet printing was carried out in the same manner as in Example 1 except that the water-repellent substance was changed to 3 parts of a silicone resin (Palon MF52, manufactured by Shin-Etsu Chemical Co., Ltd.) in the ink-receiving layer coating material of Example 1. A recording medium was created.

Example 3 Ink-jet printing was carried out in the same manner as in Example 1 except that the water-repellent substance was changed to 5 parts of a silicone resin (Palon MF52, manufactured by Shin-Etsu Chemical Co., Ltd.) in the paint for the ink-receiving layer of Example 1. A recording medium was created.

Comparative Example 1 An ink jet recording medium was prepared in the same manner as in Example 1 except that the water-repellent substance was changed to 2 parts of a fluororesin (TG410, manufactured by Daikin Industries, Ltd.) in the ink receiving layer coating material of Example 1. It was created.

Comparative Example 2 An ink jet recording medium was prepared in the same manner as in Example 1 except that the water-repellent substance was changed to 10 parts of a fluororesin (TG410, manufactured by Daikin Industries, Ltd.) in the ink receiving layer coating material of Example 1. It was created.

Example 4 The following ink-receiving layer coating composition was applied to the paper support of Example 1 in an absolute dry weight of 5.0 g / m ² to prepare an ink jet recording medium.

"Coating for ink receiving layer" Silanol-modified polyvinyl alcohol (R-1130, manufactured by Kuraray Co., Ltd.) 48
Parts, amorphous synthetic silica (Fine Seal X-37, manufactured by Tokuyama Corporation) 100 parts, cationic agent (Saftomer ST-3)
300 parts, manufactured by Mitsubishi Chemical Corporation), 10 parts of an acrylic resin (Chuo Rika Bond FK820, manufactured by Chuo Rika Co.), 10 parts of an antifoaming agent (manufactured by San Nopco), and a silicone resin as a water repellent substance (Palon MF52, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to 100 parts of silica in an amount of 3 parts to adjust the solid content to 14% to obtain a paint for an ink receiving layer.

Example 5 Ink-jet printing was carried out in the same manner as in Example 4 except that the water-repellent substance was changed to 6 parts of a silicone resin (Palon MF52, manufactured by Shin-Etsu Chemical Co., Ltd.) in the coating material for the ink-receiving layer of Example 4. A recording medium was created.

Comparative Example 3 Ink-jet printing was carried out in the same manner as in Example 4 except that the water-repellent substance was changed to 10 parts of a silicone resin (Palon MF52, manufactured by Shin-Etsu Chemical Co., Ltd.) in the ink receiving layer coating material of Example 4. A recording medium was created.

Measurement of Contact Angle The contact angle was measured according to TAPPI standard T458-84. As a measuring solution, a wetting index standard solution No. manufactured by Wako Pure Chemical Industries, Ltd. Using an automatic contact angle measuring device of DAT1100-FIBRO System (manufactured by Mabbo Co., Ltd.), the pressure was dropped to 0.
One second later, the contact angle of the measurement solution was measured.

Measurement of Absorption Time As a measuring solution, wetting index standard solution No. manufactured by Wako Pure Chemical Industries, Ltd.
40 (surface tension 40 dyne / cm), 5 to 10
5 μl was sampled with a μl sampling syringe, and the time required for the gloss of the measurement liquid dropped on the ink receiving layer to disappear due to moisture was visually measured.

Measurement method for line bleed and boundary bleed A commercially available ink jet printer (Canon BJC)
-420J, manufactured by Canon Inc.), solid color printing of black, cyan, magenta, yellow, red, blue, green, borders of adjacent colors, characters, and printing of white characters on black solid, and printing of character images The line bleeding of the line portion and the bleeding of the color boundary portion were visually evaluated. 5,4,3 from the best
2, 1.

[0041]

[Table 1]

[0042]

As described above, the surface of the ink receiving layer has a contact angle of 50 to 80 degrees after 0.1 second measured using a liquid having a surface tension of 40 dyne / cm, and a surface tension of 40 dyn.
e / cm of the liquid was collected with a syringe to obtain 5 μl, and the time required for the liquid dropped on the ink receiving layer to be absorbed by the ink receiving layer was 60 μl.
An ink jet recording medium having a speed of not more than seconds has excellent printability in both line blur and boundary blur.

Claims (2)

[Claims] In an ink jet recording medium provided with an ink receiving layer containing a pigment and an adhesive on at least one surface of a support, the surface of the ink receiving layer has a surface tension of 40 dy.
The contact angle after 0.1 second measured using a ne / cm liquid is 50 to 80 degrees, and 5 μl of a liquid having a surface tension of 40 dyne / cm is collected with a syringe, and the liquid dropped on the ink receiving layer is an ink. An ink jet recording medium, wherein the time for absorption in the receiving layer is 60 seconds or less. 2. The ink jet recording medium according to claim 1, wherein the ink receiving layer contains a water repellent substance.