JPH10278414A - Ink jet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a high-speed recording, and improve suitability for cutting by a guillotine by providing an ink receiving layer containing a pigment and a binder on one side of a support, applying a liquid containing a polyethylene emulsion to the other side and specifying a static friction factor between one side and the other side of a recording sheet below a specified value. SOLUTION: An ink-receiving layer containing a pigment and a binder is provided on one side of a support. As a dye used for the ink receiving layer, an amorphous synthetic silica is preferable because it is excellent in ink- absorptive property, and develops bright print and image colors. And a coating liquid containing a polyethylene emulsion is applied to the rear side of a recording sheet, and a static friction factor between the surface side and the rear side of the recording sheet is set at 0.8 or less. As coating the polyethylene emulsion to the rear side of the recording sheet reduces the amount of coating as compared with causes where other lubricant is used and a trouble of degrading the brightness of ink colors.

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 has a high ink absorption, can record a vivid color image at a high speed, and has excellent guillotine cutter cutting suitability.

[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 sheet having more advanced characteristics has been required. In particular, due to improvements in printing speed, resolution, saturation, etc., properties such as high absorbency, high absorption capacity, and regular ink bleeding are required for recording sheets, and an ink receiving layer is provided on the surface. Various recording sheets have been developed.

In order to satisfy such requirements, for example, amorphous synthetic silica having excellent ink absorbency is used as a pigment, and a water-soluble self-emulsifying cationic acrylic copolymer latex is used as a binder. The use of such a recording sheet has been proposed (Japanese Patent Application No. 5-260198), in which the ink absorption speed is high and the recording density is high, so that images and prints without blurring can be obtained. However, when an ink receiving layer containing a porous pigment such as amorphous synthetic silica is provided, although the recording characteristics are excellent, the friction on the surface becomes extremely large, resulting in a trouble. In other words, the ink jet recording sheet has excellent quality as ink jet paper, but when the sheet bundle is cut into a cut sheet product with a guillotine cutter, the blade stops halfway when cutting many sheet bundles, or Even if it can be cut, the size of the product tends to be irregular, and the guillotine cutter is not suitable for cutting at present.

As described above, despite excellent recording quality being obtained at present, an ink jet recording sheet compatible with guillotine cutter cutting suitability has not been developed.

[0005]

The present invention relates to an ink jet recording sheet, and more particularly, to an ink jet recording sheet which has a high ink absorption, can record a vivid color image at a high speed, and has excellent guillotine cutter cutting suitability. Is what you do. That is, the present invention relates to an ink jet recording system such as an aqueous ink jet printer, an ink jet plotter, etc., in which the ink absorption speed is high, the spread and bleeding of the ink dots is small, the ink color is vivid, and the dot shape is good and the edge is sharp. The present invention provides an ink jet recording sheet that can provide a high-resolution image and a high-speed image, and that is excellent in guillotine cutter cutting suitability.

[0006]

Means for Solving the Problems In order to improve the suitability for cutting the guillotine cutter, the relationship between the physical properties of the ink jet recording sheet and the suitability for cutting the guillotine cutter was intensively studied.
It has been found that a recording sheet having a static friction coefficient based on No. 7 of 0.8 or less has extremely excellent guillotine cutter cutting suitability. In addition, when a large amount of a porous pigment such as amorphous synthetic silica having excellent ink absorption and a vivid color is used as a pigment, the coefficient of static friction between the front and back surfaces of the recording sheet increases, and therefore, The guillotine cutter was found to be less suitable for cutting. Therefore, it was studied to lower the static friction coefficient by adding various lubricants to the ink receiving layer.However, in order to reduce the static friction coefficient, a large amount of the lubricant must be added, and until the static friction coefficient becomes 0.8 or less. When added, the ink absorptivity deteriorated and did not solve the problem.

[0007] The present invention includes the following aspects. [1] An ink jet recording sheet in which an ink receiving layer containing a pigment and a binder is provided on one surface of a support, and a polyethylene emulsion-containing liquid is applied to the other surface of the support, and the recording sheet is provided. Coefficient of static friction between one surface and the other surface (based on JIS P8147) is 0.8
The following ink jet recording sheet. [2] The ink jet recording sheet according to [1], wherein the pigment of the ink receiving layer contains amorphous synthetic silica. [3] The ink jet recording sheet according to [1] or [2], wherein the support is paper. [4] The ink jet recording sheet according to [2] or [3], wherein 50% or more of the pigment in the ink receiving layer is amorphous synthetic silica.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a support, paper, coated paper, synthetic paper, resin film, resin laminated paper and the like can be used, but paper is preferred. As the pulp material contained in the paper of the support, groundwood pulp, sulfite pulp, kraft pulp, semi-wood such as conifers such as red pine, black pine, spruce pine, fir pine, and cedar, and hardwood such as beech, hippo, and shinoki It is appropriately selected from chemical pulp, chemical ground pulp, refiner ground pulp and waste paper pulp.

The paper used as a support in the present invention includes:
In addition to the above wood pulp, a pigment is usually added internally. Examples thereof include inorganic pigments such as clay, talc, calcium carbonate, calcined clay, aluminum oxide, aluminum hydroxide, and titanium oxide, and organic pigments such as urea resin-based fine particles. Furthermore, as needed, rosin-based, alkyl ketene dammer, succinic acid and other internally added sizing agents, sulfuric acid bands, fixing agents such as cationic starch, polyacrylamide polymers, and paper strength enhancers such as starch 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 hydroxylethylated starch and derivatives thereof, polyvinyl alcohol and derivatives thereof, styrene, alkyd, polyamide, acrylic, olefin, maleic acid, acetic acid The surface treatment may be performed with a synthetic resin system composed of a polymer such as vinyl or two or more copolymers, and a surface sizing agent such as a synthetic resin emulsion system or a wax system. In order to adjust the thickness of the paper, known equipment such as a machine calendar and a carper calendar may be used as necessary.

An ink receiving layer containing a pigment and a binder is provided on one side of the support. Examples of the pigment used in the ink receiving layer include alumina, hydrated alumina sol, aluminum silicate, magnesium silicate, precipitated calcium carbonate, heavy calcium carbonate, calcium silicate, aluminum hydroxide, zeolite, calcined clay, kaolin clay. And white pigments such as talc, white carbon, and organic pigments (plastic pigments), and two or more kinds can be used in combination. Among them, amorphous synthetic silica is preferable because it has excellent ink absorbency and vivid coloration of prints and images. More preferably, amorphous synthetic silica is used at 50% or more of the pigment.

The use ratio of the pigment is preferably about 40 to 90% with respect to the solid content of all the ink receiving layers. 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.

Examples of the binder used in the ink receiving layer include polyvinyl alcohol, silanol-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, proteins such as casein, starch derivatives such as starch and oxidized starch, and various latexes. The use ratio of such a binder is preferably about 5 to 30% based on the solid content of all the ink receiving layers. In order to improve the coloring property, a cationic resin such as a water-soluble resin may be contained. Examples of the cationic resin include polyalkylene polyamines such as polyethylene amine and polypropylene amine, or derivatives thereof,
An acrylic resin having a tertiary amino group or a quaternary ammonium group, diallyldiamine, etc. can be exemplified. The cationic resin is added in an amount of 1 to 30 parts by weight based on 100 parts by weight of the pigment. In addition, pigment dispersants, defoamers, colorants, fluorescent dyes, antioxidants, ultraviolet absorbers, viscosity modifiers, cross-linking agents, and the like are appropriately used as additives according to manufacturing conditions, printing quality, and required performance. Is done.

Known coating equipment such as a bar coater, a roll coater, an air knife coater, a blade coater, a rod coater, and a gravure coater are used for coating the paint. The sheet provided with the ink receiving layer on the support,
Although it is possible to use the recording sheet of the present invention as it is, for example, it is possible to impart a smoothness to the surface by performing a super calender or a gloss calender treatment.

Although the coating amount of the ink receiving layer is not particularly limited, it is about 1 to 30 g / m ² , preferably ² to 30 g / m 2.
It is in the range of 20 g / m ² . If the coating amount of the ink receiving layer is small, the ink absorption capacity will be insufficient, the image will run out, the color will blur, the image will be blurred, and the drying will be slow, so the ink will adhere to the paper discharge roll etc. of the printer And
Dirt may occur. Conversely, if the coating amount is large, the coating layer is thick and the adhesiveness to paper is weak, and the coating layer that has peeled off may cause problems such as clogging of the head nozzle. It is also expensive.

In the present invention, the coating liquid containing polyethylene emulsion is applied to the back surface of the recording sheet, and the coefficient of static friction between the front surface and the back surface of the recording sheet is set to 0.8 or less. As a method of coating, before or after the ink receiving layer coating step, a method of coating with a known coating equipment such as a bar coater or a roll coater, when forming a base paper as a support, a size press liquid is used. At least one such as adding a polyethylene emulsion can be employed. The present invention is characterized in that a polyethylene emulsion is applied to the back surface of the recording sheet (the back surface of the surface provided with the receiving layer). On the other hand, when no polyethylene emulsion is contained at all and other lubricants (paraffin wax, stearic acid, calcium stearate, zinc stearate, special ester wax, etc. are used), the effect of lowering the coefficient of static friction is small, It is necessary to increase the amount of coating, and in that case, there is an adverse effect of deteriorating the vividness of the color development of the ink.

The amount of coating on the back side is not particularly limited, but is 0.001% by dry coating amount of polyethylene.
About 1 g / m ² . However, a coating amount is required so that the coefficient of static friction between the front and back surfaces of the recording sheet is 0.8 or less. Aqueous resins such as oxidized starch, pigments, pigment dispersants, defoamers, colorants, fluorescent dyes, antioxidants, ultraviolet absorbers, viscosity modifiers, cross-linking agents, etc. may be used as needed in the polyethylene emulsion coating liquid. Can also be added.

[0017]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto. In the examples, "parts" and "%" indicate "parts by weight" and "% by weight", respectively, unless otherwise specified. Example 1 5 parts of amorphous silica was added to a slurry of 100 parts of hardwood kraft pulp, 0.4 part of cationic starch and 0.3 part of a synthetic oligomer-based internal sizing agent were added, and mixed well to make paper. 10% water as raw material using Fourdrinier multi-cylinder paper machine
Until dried, sized 2% aqueous solution of oxidized starch in both by a press (total dry coating weight) 1 g / m ² coated, dried, the basis weight 75 g / m ² and dried to 7% moisture quality paper Manufactured. One side (one side) of the obtained high-quality paper was coated with an aqueous paint-1 at an absolute dry weight of 6 g / m ² using an air knife coater.
Dried. Then, on the back side where the paint-1 is not applied,
Using a bar coater, a polyethylene emulsion (trade name: Nopcoat PEM17, manufactured by San Nopco) was charged to 0.03.
g / m ^{2 was} applied and dried, and subjected to a smoothing treatment with a super calender so that the Oken type smoothness (JAPAN TAPPI No. 5) was 80 seconds, to produce an inkjet recording sheet.

Paint-1 Amorphous synthetic silica (trade name: Fine Seal X-37,
60 parts of Tokuyama, 15 parts of oxidized starch (trade name: Ace A, manufactured by Oji Cornstarch), 8 parts of modified polyvinyl alcohol (trade name: R-1130, manufactured by Kuraray), self-emulsifying cationic resin latex (trade name: 11 parts of Sumikaflex CGC-201NF, manufactured by Sumitomo Chemical Co., Ltd., 6 parts of a cationic resin (trade name: Sumireze Resin 1001, manufactured by Sumitomo Chemical Co., Ltd.), and a 13% composition composed of water are dispersed by a high-speed stirrer. did.

Example 2 In manufacturing the ink jet recording sheet of Example 1,
On the back of the recording sheet
0.03g / m^Two0.01g / m instead of applying ^Twocloth
Ink jet recording in the same manner as in Example 1 except that
Sheet was obtained. Example 3 Production of the ink jet recording sheet of Example 1 was carried out.
And paint-1 amorphous synthetic silica (trade name:
X-37, manufactured by Tokuyama)
Synthetic silica (trade name: Fine Seal X-37, Tokuya)
40 parts, alumina (trade name: CAH-3000,
Sumitomo Chemical Co., Ltd.) except that it was 20 parts.
Thus, an ink jet recording sheet was obtained.

Example 4 In the production of the ink jet recording sheet of Example 1, the size press liquid was changed to 2% oxidized starch and 0.2% polyethylene emulsion (trade name: Nopcoat PEM17) instead of the 2% aqueous solution of oxidized starch. Was obtained in the same manner as in Example 1 except that an aqueous solution containing the same was used, and that the backside coating of the polyethylene emulsion was not performed.

Comparative Example 1 An ink jet recording sheet was obtained in the same manner as in Example 1 except that the polyethylene emulsion was not applied to the back surface of the recording sheet in the production of the ink jet recording sheet of Example 1. Example 5 In the production of the ink jet recording sheet of Example 1, instead of 60 parts of amorphous synthetic silica (trade name: Fine Seal X-37, manufactured by Tokuyama) of Paint-1, amorphous synthetic silica (trade name) was used. Name: Fine Seal X-37, 29 parts by Tokuyama, calcium carbonate (trade name: Univer 7)
0, manufactured by Shiraishi Kogyo Co., Ltd.), and an ink jet recording sheet was obtained in the same manner as in Example 1.

Comparative Example 2 An aqueous dispersion of calcium stearate (trade name: Nopcoat C-1) was used instead of applying 0.03 g / m ^{2 of a} polyethylene emulsion to the back of the recording sheet in Example 1.
04-HS, manufactured by San Nopco) was applied in the same manner as in Example 1 except that 1.0 g / m ^{2 was} applied to obtain a sheet for ink jet recording.

Comparative Example 3 In the production of the ink jet recording sheet of Example 1, the polyethylene emulsion was not coated on the back side,
An ink jet recording sheet was obtained in the same manner as in Example 1, except that 10 parts of a polyethylene emulsion (trade name: Nopcoat PEM17) was added to Paint-1.

The following evaluation tests were performed on the respective ink jet recording sheets thus obtained, and the results are shown in Table 1. [Coefficient of Static Friction] The coefficient of static friction between the front surface and the back surface of the recording sheet was measured based on the horizontal method of JIS P8147. [Ink Absorption] Time until the printed ink dries using an inkjet printer (manufactured by Canon, BJC-820J) (reflected light on the recording surface is visually evaluated.
The point at which the reflection disappeared was judged to be a dry state). 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

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

[Suitability of guillotine cutter] Using a guillotine cutter manufactured by Yoda Machine Industry Co., Ltd. (Fuji MNC-2000), 1,000 sheets of sheet bundles were cut to A4 size, and the suitability for cutting was evaluated according to the following criteria. …: 1000 sheet bundles can be cut with high dimensional accuracy △: 1000 sheet bundles can be cut, but dimensional accuracy is poor × １０００ 1000 sheet bundles cannot be cut, and blade stops halfway

[0027]

[Table 1]

[0028]

The ink-jet recording sheet of the present invention is an ink-jet recording sheet which is excellent in ink absorbency and vividness of coloring, and excellent in guillotine cutter cutting suitability.

Claims (2)

[Claims] An ink jet recording sheet comprising an ink receiving layer containing a pigment and a binder provided on one surface of a support, wherein a liquid containing a polyethylene emulsion is applied on the other surface of the support. An ink jet recording sheet having a coefficient of static friction (based on JIS P8147) between one surface and the other surface of the recording sheet of 0.8 or less. 2. The ink jet recording sheet according to claim 1, wherein the pigment of the ink receiving layer contains amorphous synthetic silica.