JP3141753B2 - Inkjet recording sheet - Google Patents

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, and more particularly to an ink-jet recording sheet which is capable of high-speed recording, has no bleeding of recording, and has excellent coloring.

[0002]

2. Description of the Related Art In recent years, with the technical progress of an ink jet color printer for producing a color hard copy at high speed, it has become possible to obtain a clear image and excellent print quality. However, on the other hand, in order to further improve the print quality, saturation, appearance, and image, a recording material having higher characteristics has been required. In particular, high absorption, high absorption capacity, regular ink bleeding, etc., for recording materials due to improvements in printing speed, resolution, saturation, etc.
As higher properties are required, various recording sheets having an ink receiving layer on the surface have been developed.

For example, Japanese Unexamined Patent Publication No. 55-51585 discloses a method having a coating layer composed of non-colloidal silica (particle size: 0.1-10.0 μm) and a polymer binder.
In JP-A-148584, an ink receiving layer containing a porous inorganic pigment (natural zeolite, synthetic zeolite, diatomaceous earth, fine silicic acid, synthetic mica, etc.) having a function of adsorbing and retaining a dye is provided on the surface of a substrate. A recording sheet is disclosed. However, in these recording papers, if the coating amount is small, the bleeding of the ink is poor, and if the coating amount is large, the bleeding is eliminated, but there is a problem that the coating layer peels off and powder falls off.

[0004] To solve this problem, there has been reported a paper in which the amount of a binder is increased to improve the strength, but such a recording paper has a shortage of ink absorption capacity, bleeding becomes remarkable, and image quality becomes high. And it was difficult to reproduce a desired resolution and an intermediate color. Japanese Patent Application Laid-Open No. 62-288076 discloses an attempt to improve the adhesive strength by using a water-insoluble resin obtained by reacting polyvinyl alcohol, acrylic acid and methyl methacrylate. However, since the water-insoluble resin is anionic, the fixability of the ink mainly containing anionic is also poor. Further, when a large amount of the water-insoluble resin is blended, there is a problem such as bleeding of the ink over time, and conversely, when the amount is small, the effect of improving the adhesive strength is insufficient.

As described above, various proposals have been made for an ink jet recording sheet. However, an ink jet recording sheet which is excellent in ink bleeding, coloring and absorptivity, and excellent in surface strength has not yet been developed.

[0006]

SUMMARY OF THE INVENTION The present invention provides an ink jet recording sheet which is capable of recording an image having high color and no bleeding at a high speed and has excellent surface strength in an ink jet recording system such as an ink jet printer and an ink jet plotter. Is what you do. The present invention relates to an ink jet recording system used for image recording and printing printers using an aqueous ink, in which the ink absorption speed is fast, the spread and bleeding of the ink dots is small, the color of the ink is vivid, and the dot shape is large. Provided is an ink jet recording sheet capable of giving a good image with sharp edges and printing, and thus capable of recording a high-resolution image at a high speed.

[0007]

The present invention includes the following aspects. [1] In an ink jet recording sheet provided with an ink receiving layer containing a pigment and a binder on at least one surface of a support, a self-emulsifying cationic resin comprising a water-insoluble acrylic copolymer as a binder is provided. An ink jet recording sheet comprising a resin.

[2] The ink jet recording sheet according to [1], wherein the ink receiving layer further contains a water-soluble cationic resin. [3] The ink jet recording sheet according to [1] or [2], wherein the ink receiving layer further contains another water-soluble resin. [4] The ink receiving layer contains a self-emulsifying cationic resin made of a water-insoluble acrylic copolymer in an amount of 5 to 70% by weight based on the total binder [1], [2] or [3].
The sheet for inkjet recording according to the above.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Conventionally, an emulsifier such as anionic, cationic, nonionic or polymer known in the art is used for imparting dispersion stability to a resin comprising a water-insoluble acrylic copolymer. However, it has been found that these emulsifiers greatly impair the adhesion and water resistance of the coating film, and that the emulsifier affects the surface tension of the coating layer, and that the ink bleeds upon inkjet recording. Therefore, in the present invention, a self-emulsifying cationic resin made of a water-insoluble acrylic copolymer is contained as a binder for the ink receiving layer. The self-emulsifying cationic resin composed of a water-insoluble acrylic copolymer used in the present invention is prepared as a self-emulsifying latex, and does not contain an emulsifier.

The self-emulsifying cationic resin comprising a water-insoluble acrylic copolymer used in the present invention contains a monomer containing an alkyl ester of acrylic acid or methacrylic acid and is obtained by soap-free polymerization. In this acrylic copolymer, a cationic functional group is chemically bonded. Examples of the alkyl ester of acrylic acid or methacrylic acid include alkyl esters having about 1 to 18 carbon atoms.

The main monomers constituting the water-insoluble acrylic copolymer include methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like. For example, other monomers can be copolymerized.
The method for producing the self-emulsifying cationic resin is not particularly limited, but includes a seed method (a method in which a water-soluble or water-dispersible polymer is prepared in advance and a monomer is added to the resultant as a seed and polymerized), Emulsifier method (polymerization method in which a compound having an ethylenically unsaturated bond and a hydrophilic group in the molecule is used in place of a conventional emulsifier), oligomer method (oligomer generated in the system has the same function as a surfactant) Polymerization method utilizing the above method) and the like.

Although not necessarily limited to the following examples, the cationic functional group includes a tertiary amino group,
Alternatively, a quaternary ammonium base or the like can be used. Since the self-emulsifying cationic acrylic copolymer is cationic, the fixing property of the dye in the ink receiving layer is improved, the water resistance is excellent, and the coloring property of the dye is improved. Although the use ratio of the self-emulsifying cationic acrylic copolymer latex in the binder is not particularly limited, it is preferably 3% by weight or more, more preferably 5% by weight, of the total binder as a solid content.
７０70% by weight. If the amount is too small, the effect of improving the bleeding of the ink may not be sufficiently obtained. On the other hand, if the binder does not contain a water-soluble cationic resin and / or other water-soluble resin as described below, the bleeding improving effect may be obtained. However, the ink absorption time may be long.

In the ink receiving layer, in addition to the self-emulsifying cationic acrylic copolymer latex, polyvinyl alcohol, polyvinyl alcohol derivatives modified with silanol groups, proteins such as casein, starch, oxidized starch, etc. Other water-soluble resins such as derivatives of the above can also be used in combination. Thereby, the ink absorption speed can be further increased. Although not particularly limited, when other water-soluble resin is contained, about 20 to 2,000 parts by weight is added to 100 parts by weight of the self-emulsifying cationic resin.

When a water-soluble cationic resin is contained in the ink receiving layer, a recording sheet having more excellent coloring properties can be obtained. Examples of the water-soluble cationic resin include polyethyleneimine, polyvinylpyridine, polydialkylaminoethyl methacrylate, polydialkylaminoethyl acrylate, polydialkylaminoethyl methacrylamide,
Compounds such as polydialkylaminoethyl acrylamide, polyepoxyamine, polyamidoamine, dicyandiamide-formalin condensate, dicyandiamide polyalkyl-polyalkylenepolyamine condensate, polydimethyldiallylammonium chloride, polyvinylamine, polyallylamine and the like, and modified products thereof Can be illustrated. Although not particularly limited, when a water-soluble cationic resin is contained, about 50 to 1500 parts by weight is added to 100 parts by weight of the self-emulsifying cationic resin.

The pigment used in the ink receiving layer of the present invention includes amorphous synthetic silica, aluminum silicate, magnesium silicate, precipitated calcium carbonate, heavy calcium carbonate, calcium silicate, aluminum hydroxide, zeolite, calcined clay, Examples thereof include white pigments such as kaolin clay, talc, white carbon, and organic pigments (plastic pigments), and two or more kinds can be used in combination. Among them, amorphous synthetic silica, alumina, and hydrated alumina sol are preferable because of their good ink absorbency and high color density of the ink. The use ratio of such a pigment is preferably about 40 to 90% by weight based on the solid content of the entire ink receiving layer. When the amount of the pigment is small, the ink absorbency may be insufficient, and when the amount is large, the strength of the ink receiving layer may be reduced.

Other additives include a pigment dispersant, an antifoaming agent, a colorant, an antioxidant, an ultraviolet absorber, a viscosity modifier,
A cross-linking agent or the like is appropriately used according to the manufacturing conditions, printing quality, and required performance. Known coating equipment such as a bar coater, an air knife coater, a blade coater, and a gravure coater are applied for coating the paint. The sheet provided with the ink receiving layer on the support can be used as it is as the recording sheet of the present invention. For example, it can be treated with a super calender, a gloss calender, or the like to impart smoothness to the surface. . The coating amount of the ink receiving layer obtained in the present invention is not particularly limited, 1 to 30 g / m ² approximately, and preferably from 2 to 20 g / m ^2.

If the coating amount of the ink receiving layer is small, the ink absorption capacity is insufficient, the image runs out, the color blurs, the image is blurred, the drying is slow, and the ink is discharged onto the paper discharge roll of the printer. May adhere and become dirty. On the other hand, if the amount is too large, the adhesiveness to paper becomes weak because the coating layer is thick, and a problem such as clogging of the head nozzle may be caused by the peeled-off coating layer. It is also expensive.

Examples of the support include paper made of cellulose pulp, synthetic paper, and a transparent or opaque sheet mainly containing a synthetic resin. Pulp materials contained in paper include conifers such as Akamatsu, Kuromatsu, Ezomatsu, Todomatsu and Cedar,
It is appropriately selected from groundwood pulp, sulfite pulp, kraft pulp, semi-chemical pulp, chemical ground pulp, refiner ground pulp and waste paper pulp mainly using hardwood such as beech, hippopotamus and Shinoki. In addition to the wood pulp described above, a pigment is usually internally added to the paper used as the support in the present invention. Examples thereof include inorganic pigments such as clay, talc, calcium carbonate, calcined kaolin, aluminum oxide, aluminum hydroxide, and titanium oxide, and organic pigments such as urea resin-based fine particles. In addition, rosin-based, alkyl ketene dimer, alkenyl succinic acid and other internal sizing agents, sulfuric acid bands, cationic starch and other fixing agents, polyacrylamide-based polymers, starch and other paper strength enhancers, etc. are appropriately selected as necessary. The paper is internally added, and a base paper made by a paper machine is used.

If necessary, rosin, petroleum resin, oxidized starch, acetylated starch, starch such as hydroxyethylated starch and derivatives thereof, polyvinyl alcohol and derivatives thereof, styrene, alkyd, polyamide, acrylic, olefin, The sizing treatment may be performed with a synthetic resin based on a polymer such as maleic acid or vinyl acetate or two or more copolymers, or a surface sizing agent such as a synthetic resin emulsion or wax.

In order to adjust the thickness, known equipment such as a machine calender and a super calender may be used if necessary. As the resin film used for the support, polyester resins and olefin resins can be used as thermoplastic resins. As polyester resin,
Examples include polyethylene terephthalate, polybutylene terephthalate, and polycyclohexene terephthalate, and examples of the olefin resin include those made of polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, or those containing these as main components. it can. Polystyrene and acrylate copolymers can also be used as a mixture of other thermoplastic resins. A film formed by stretching these thermoplastic resins in the machine direction and / or the transverse direction is also used.

Alternatively, a film may be formed by mixing an inorganic fine powder into the thermoplastic resin, and this may be biaxially stretched to form a paper-like layer (synthetic paper). In the present invention, a multilayer film obtained by laminating a plurality of such films can be used as a support. For example, it is effective to use a two- or three-layer film in which a paper-like layer is provided on both sides or one side of a base material layer, or a three- to five-layer film in which a surface layer is formed on at least one side of the paper-like layer. It is a target. What made a thermoplastic resin into a paper-like layer is generally known as synthetic paper. The opacity of such a film is not particularly limited in the present invention.

[0022]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but it should be understood that the present invention is not limited by these examples. In the following, “parts” and “%” indicate “parts by weight” and “% by weight” of a solid content (non-volatile content).

Reference Example 1 20 parts of light calcium carbonate was bleached from hardwood kraft pulp 1.
0.8 parts of cationic starch,
0.11 part of an alkenyl succinic anhydride-based neutral sizing agent was added and mixed well to obtain a papermaking raw material, and the water content was dried to 10% using a fourdrinier multi-cylinder paper machine. A 6% solution was applied on both sides at 5 g / m ² , dried, and dried to a moisture content of 7% to produce a high quality paper of 82 g / m ² per square meter. Aqueous paint-1 was applied on one side of the obtained high-quality paper using a bar coater in an absolute dry weight of 10 g / m ² to produce an ink jet recording sheet.

Paint-1 Amorphous synthetic silica (trade name: Fine Seal, manufactured by Tokuyama) 73%, polyvinyl alcohol (trade name: PVA)
117, manufactured by Kuraray Co., Ltd.) 16.2%, self-emulsifying cationic resin latex made of water-insoluble acrylic copolymer (trade name: Sumikaflex 3911, manufactured by Sumitomo Chemical Co., Ltd.) 10.8%

Example 1 A water-based coating material-2 was applied on one side of the high-quality paper used in Reference Example 1 using a bar coater at an absolute dry weight of 15 g / m ² to produce an ink jet recording sheet.

Paint-2 : 72% amorphous synthetic silica (trade name: Fine Seal, manufactured by Tokuyama), polyvinyl alcohol (trade name: PVA)
117, Kuraray) 2.2%, oxidized starch (trade name:
Ace A, manufactured by Oji Corn Starch) 8%, polydiallyldimethylammonium chloride having a molecular weight of about 50,000 as a water-soluble cationic resin (trade name: PAS-H-
5L: 6%, self-emulsifying cationic resin composed of a water-insoluble acrylic copolymer (trade name: Sumikaflex 3911, manufactured by Sumitomo Chemical Co., Ltd.) 1
0.8%

Example 2 A coating layer was formed on one side of the high-quality paper used in Reference Example 1 using a bar coater by applying 5 g / m ^{2 of} water-based paint-3 on a dry basis to form a coating layer. Was manufactured.

Paint-3 Amorphous synthetic silica (trade name: Fine Seal, manufactured by Tokuyama) 20%, calcium carbonate (trade name: Univer 70,
20%, polyvinyl alcohol (trade name: PVA R-1130, manufactured by Kuraray) 49%, polyoxypropylene methyldiethylammonium chloride having 9 oxypropylene chains as a water-soluble cationic resin (trade name: Shiraishi Kogyo) Adekacol CC-9, Asahi Denka Kogyo Co., Ltd.) 8%, self-emulsifying cationic resin made of water-insoluble acrylic copolymer (trade name: Sumikaflex 3911, Sumitomo Chemical Co., Ltd.) 3%

Example 3 A water-based coating material-4 was applied to one side of the high-quality paper used in Reference Example 1 using a bar coater in an absolute dry weight of 10 g / m ² to produce an ink jet recording sheet.

Paint-4 Alumina (trade name: CAH-3000: manufactured by Sumitomo Chemical) 9
0%, polyvinyl alcohol (Product name: PVA 11
7, Kuraray Co., Ltd.) 2.4%, water-soluble cationic resin having a molecular weight of about 50,000 polydiallyldimethylammonium chloride (trade name: PAS-H-5L, manufactured by Nitto Boseki Co., Ltd.) 2%, water-insoluble acrylic resin Self-emulsifying cationic resin made of polymer (trade name: Boncoat S
FC-302, manufactured by Dainippon Ink, emulsion polymer having an average particle size of 260 nm, Tg of 0 ° C) 5.6%

Example 4 Synthetic paper having a multilayer structure containing an inorganic pigment (trade name: YUPO FPG)
-110, made of Oji Oil Chemical Synthetic Paper, thickness of 110 μm), using a bar coater on one side, paint-2 was dried at an absolute dry weight of 15 g /
m ^{2 was} applied to produce an ink jet recording sheet.

Example 5 Polyethylene terephthalate resin film (thickness: 75 μm)
m, one side was 20 g / m ² coated with the coating -2 absolute dry weight using a bar coater manufactured by Toray Industries, Inc.), was prepared an ink jet recording sheet.

Example 6 A water-based coating material-8 was applied to one side of the high-quality paper used in Reference Example 1 using a bar coater at an absolute dry weight of 10 g / m ² to produce an ink jet recording sheet.

Paint-8 Self-emulsifying cationic resin comprising 60% amorphous synthetic silica (trade name: Fine Seal, manufactured by Tokuyama) and a water-insoluble acrylic copolymer (trade name: Boncoat SFC-
302, manufactured by Dainippon Ink, an emulsion polymer having an average particle size of 260 nm, Tg of 0 ° C) 28%, polydiallyldimethylammonium chloride having a molecular weight of about 50,000 as a water-soluble cationic resin (trade name: PAS-H-5L,
12%

[0035] Except that does not use the self-emulsifying cationic resin consisting of acrylic copolymer water-insoluble Comparative Example 1 Reference Example 1 was repeated Example 1. Except that in Comparative Example 2 Example 1 not using the self-emulsifying cationic resin consisting of acrylic copolymer water-insoluble The procedure of Example 1 was repeated.

Comparative Example 3 A water-based coating material 5 was applied to one side of the high-quality paper used in Reference Example 1 using a bar coater at a dry weight of 10 g / m ² to produce an ink jet recording sheet. Paint-5 Amorphous synthetic silica (trade name: Fine Seal, manufactured by Tokuyama) 40%, polyvinyl alcohol (trade name: PVA)
117, manufactured by Kuraray Co., Ltd., a cationic resin emulsion comprising a water-insoluble acrylic copolymer obtained by emulsion polymerization using an emulsifier (trade name: Boncoat VO-
8, Dainippon Ink) 48%

Comparative Example 4 A water-based coating material 6 was applied to one side of the high-quality paper used in Reference Example 1 using a bar coater at a dry weight of 10 g / m ² to produce a sheet for ink jet recording. Paint-6 Alumina (trade name: CAH-3000, manufactured by Sumitomo Chemical Co., Ltd.) 67%, polyvinyl alcohol (trade name: P
VA 117, manufactured by Kuraray) 16.2%, polyoxypropylene methyl diethylammonium chloride having a chain composed of 9 oxypropylenes as a water-soluble cationic resin (trade name: Adekacol CC-9, manufactured by Asahi Denka Kogyo Co., Ltd.) 6%, a cationic resin made of a water-insoluble vinyl acetate copolymer obtained by emulsion polymerization using an emulsifier (trade name: Iodozol CE-58, manufactured by Kanebo NSC Ltd.) 10.8%

Comparative Example 5 An ink-jet recording sheet was produced by applying 18 g / m ² of paint-6 on a single side of the synthetic paper YUPO FPG-110 used in Example 4 using a bar coater in an absolutely dry amount. .

Comparative Example 6 An aqueous paint-7 was applied on one side of the high-quality paper used in Reference Example 1 using a bar coater at an absolute dry weight of 10 g / m ² to produce an ink jet recording sheet.

Paint-7 Amorphous synthetic silica (trade name: Fine Seal, manufactured by Tokuyama) 67%, polyvinyl alcohol (trade name: PVA)
117, Kuraray Co., Ltd.) 16.2%, water-soluble cationic resin polydiallyldimethylammonium chloride (trade name: PAS-H-5L, manufactured by Nitto Boseki Co., Ltd.) 6%, by emulsion polymerization using an emulsifier 10.8% of the obtained anionic resin, a water-insoluble carboxy-modified styrene / butadiene copolymer (trade name: JSR0593, manufactured by Nippon Synthetic Rubber)

Table 1 shows the evaluation results of these coated papers. The following method was used to evaluate the ink jet recording characteristics. (1) Ink absorptivity: The time until the printed ink dries using an inkjet printer (BJC-820J, manufactured by Canon) Was determined). The evaluation was performed in the following five stages. 5 ... less than 4 seconds 4 ... 4 to 7 seconds 3 ... 7 to 10 seconds 2 ... 10 to 15 seconds 1 ... 15 seconds or more

(2) Vividness of color development: Using an ink jet printer (BJC-820J, manufactured by Canon Inc.), yellow, magenta and cyan recording portions were visually evaluated. The evaluation was performed in the following five stages. 5: The color of the recorded portion is extremely clear 4: The color of the recorded portion is clear 3: The color of the recorded portion is normal 2 ... The color of the recorded portion is sinking 1 ... The color of the recorded part is depressed and extremely unclear

(3) Dot Shape and Thickness: Using an inkjet printer (BJC-820J, manufactured by Canon Inc.), the shape and thickness of the printed dots were observed at a magnification of 50 times using a zoom stereoscope (manufactured by Senner Co., Ltd.). The evaluation was performed in the following five stages. 5: The dot shape is a perfect circle and the dot thickness is small 4 ... The dot shape is almost a perfect circle and the dot thickness is small 3 ... Both the dot shape and the dot thickness are normal 2 ... The dot shape is defective and the dot thickness is large. 1 ... The dot shape is extremely defective and the dot thickness is extremely large.

(4) Bleeding of ink due to color mixture: inkjet printer (BJC-820J, manufactured by Canon)
The bleeding condition of a green solid printing portion (overlapping portion of two color inks of cyan and yellow) was evaluated organoleptically. The evaluation was performed in five stages. 5: No ink bleeding 4: Almost no ink bleeding 3: Ink bleeding is observed 2: ... Ink bleeding is slightly large 1 ... Ink bleeding is remarkable

(5) The surface strength was evaluated by a peel test of the surface of the ink receiving layer using a cellophane tape (Nichiban). The evaluation was performed by sensory evaluation and evaluated in three stages. 3: Excellent surface strength 2: Normal surface strength 1: Low surface strength

[0046]

[Table 1]

As can be seen from Table 1, the ink jet recording sheets obtained in the examples are excellent in all of ink absorbency, vividness of color development, dot thickening, shape, color mixture bleeding and surface strength. In contrast, the ink jet recording sheet obtained by the comparative example is
Good results were not obtained in terms of color vividness, dot thickening, shape, and color mixture bleeding. In addition, the coating of the coating material 7 prepared in Comparative Example 6 was stopped due to aggregation during the preparation of the coating material.

[0048]

The recording sheet for an ink jet printer of the present invention is excellent not only in ink absorbency and color development, but also in dot thickness, shape, and color mixture bleeding. It is also possible to print high-definition images at high speed in color printing.

Continuation of the front page (56) References JP-A-7-117332 (JP, A) JP-A 1-295878 (JP, A) JP-A-63-306074 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) B41M 5/00

Claims (1)

(57) [Claims] At least one surface according to claim 1 The support, in an ink jet recording sheet comprising an ink receiving layer containing a pigment and a binder, said binder is composed of acrylic copolymer water-insoluble self Emulsifying cationic resin and
Polyvinyl modified with vinyl alcohol and silanol groups
A group consisting of nyl alcohol derivatives, starch and oxidized starch
At least one water-soluble resin selected from the group consisting of:
Rudiallylammonium chloride, polyallylamine
And polyoxychloride having 9 oxypropylene chains
A group consisting of propylene methyl diethyl ammonium
At least one water-soluble cationic resin selected
Self-contained and water-insoluble acrylic copolymer
5 to 70 weights of self-emulsifying cationic resin with respect to all binders
A sheet for ink jet recording , characterized in that the sheet contains an amount of 0.1% by weight .