JPS61125878A - Ink jet recording sheet - Google Patents

Abstract

PURPOSE:To obtain a recoding sheet on which ink dots are relatively largely spread and the dots are substantially true circular in shape, by using a coating material comprising a pigment with a specified particle diameter, a specified binder and a specified dye fixing agent. CONSTITUTION:A coating material comprising a binder, a dye fixing agent and a pigment is applied to the surface of a base such as a paper to obtain the recording sheet. The binder comprises acetoacetylated PVA in an amount of 15-100%. A cationic dicyandiamide resin is used as the dye fixing agent. The pigment has an average particle diameter of 5-15mum. The ink jet recording sheet is so controlled that the ink dots printed on the sheet have a diameter D of about 3.4d-6.0d, where (d) is the diameter of a nozzle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording sheet 5. More specifically, the ink dot density is low, it is relatively inexpensive and high speed, the ink dots spread quickly, lateral and uniform ink dots can be obtained, and the force of force 1 can be applied to the inside of the sickle layer. The present invention relates to an inkjet recording sheet which has excellent water resistance and light resistance, and which suppresses ink penetration to an appropriate extent.

[Industrial application field]

The inkjet recording method is low noise, high speed 2 sickles,
Since it is possible to use multiple colors and make the device more compact, and can use both recording paper and VR paper, it has been widely adopted in various factor cutters, printers, computer terminals, etc. It has rapidly become popular in recent years and is now occupying an important field of information equipment.

[Prior art]

Traditionally, inkjet recording paper accepts ink,
Sucking! Since recording is performed by the inherent properties of paper, it was possible to use commercially available plain paper such as medium-quality coated paper as is without adding any special performance.

However, as demands for high-quality recording performance such as color recording become stronger, plain paper (uncoated paper) may not be able to provide sufficient performance, and recording paper suitable for the inkjet recording method or the properties of the ink is used. (Special paper, coated paper) was developed and started to be used. ! Circle.

For example, Tokukai Akira! ;A-109g3 is a method for adjusting the spread of ink dots on the recording paper surface, which is obtained by size press coating a hydrophilic polymer substance on paper having a certain Klemm water absorption. An inkjet recording paper is disclosed.

Furthermore, Japanese Patent Application Laid-Open No. 7-3469λ and Japanese Patent Application Laid-open No. 37-6-3-3 disclose inkjet recording paper which is highly water resistant and has improved recordability and storage stability.

However, the recording paper described in the above-mentioned prior art document was developed for multi-color recording which requires a high resolution with an ink dot density of 6 to 6 dots per frame.

On the other hand, absorption-type uncoated paper has traditionally been used as multicolor (pull-color) recording paper that is inexpensive and capable of high-speed recording with an ink dot density of 3 to J'' dots/H, which does not require high resolution. However, simply being an absorbent type is not enough; in order to adjust the ink absorbency, color tone, etc., uncoated paper with appropriately selected paper PMs sizing agents, fillers, etc. was generally used. .

However, with uncoated paper, there is a natural limit to the performance that can be obtained even if the pH etc. are adjusted as described above, and it has not been possible to obtain a book that is fully satisfactory in terms of uniformity of ink dot spread, etc. Furthermore, since water-based ink is mainly used in the inksheet method, it is difficult to obtain sufficient water resistance of 6''' with uncoated paper.
No satisfactory light resistance was obtained.

Therefore, the present inventors have conducted various studies in order to improve and eliminate the drawbacks of the conventional non-coated paper mentioned above, and to provide a coated recording paper that can be favorably used in the field of recording with a low ink dot density. I fell asleep. □That is, the purpose of the present invention is to
The objective is to provide a recording paper that has both the following characteristics required during inkjet recording and the characteristics required during storage after recording.The characteristics required during the above distribution are as follows: 1) The ink dots spread quickly and relatively widely on the surface of the recording sheet, (1) The spread of the ink dots is uniform and isotropic, and (m) The ink does not soak into the inside of the recording layer. It is possible to reproduce clear color tones such as yellow, magenta, cyan, and black without color stains (that is, with high saturation) by appropriately suppressing the ink. When performing multi-color recording, even if ink dots overlap on the same side of the recording paper, each ink component is instantly absorbed, and the recording surface is not smeared even during high-speed recording. It has a capacity.

On the other hand, the storage characteristics required of the recording layer sheet after being recorded by the inkjet recording apparatus are that the 1!1Idil image is not swept away by the action of water and light.

[Structure of the invention]

The present invention provides an inkjet recording sheet (for inkjet recording) in which a coating layer comprising a dye fixing agent and a pigment is provided on at least one side of a support, in which (a) the binder is made of acetoacetylated 4-lipier alcohol; (1) An inkjet recording sheet Kf characterized in that the dye fixing agent is a cationic dicyandiamide resin, and (c) the pigment has an average particle diameter of 5 to 3 μm. Further, in the present invention, the diameter O of the ink dots printed on the inkjet recording sheet is about 3.11 d to A, O d
(where d is the aperture of the nozzle) The recording sheet of the present invention relates to an inkjet recording sheet whose size is controlled to be within the range of (where d is the aperture of the nozzle), particularly preferably within the range of approximately 3.6d to 3.3d. In ``Acetoacetylated polyvinyl alcohol contained in the binder by-product, for example, the average degree of polymerization J00-2!OO1 average saponification &70~/θ
It can be produced by a conventional method such as addition reaction of diketene to the 4-rivinyl alcohol, or transesterification reaction with acetoacetate. be.

In the present invention, it is preferable that the acetoacetylated polyvinyl alcohol has an acetoacetyl group content of usually 0.1 to 20 mol %, preferably 0.5 to 10 mol %.

The binder of the present invention also includes the acetoacetylated 4
In addition to ribinyl alcohol, the following aqueous polymers can be contained as a dispersion medium or a fluidity improver.

However, the content of acetoacetylated 4-livinyl alcohol in the binder is preferably from 73 to 100%.

Examples of the aqueous polymers that can be contained in the binder as the dispersion medium include starch derivatives and their anion- or cation-modified stv vinyl alcohols, cellulose derivatives (cal materials oxymethylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, etc.). ), ammonium salts of styrene-maleic acid copolymers, and the like.

Furthermore, the binder of the present invention may optionally contain a wetting agent,
Preservatives, optical brighteners, antifoaming agents, etc. can also be included.

The "dye fixing agent" used in the present invention is a cationic dicyandiamide resin. Examples of the cationic dicyandiamide resin include dicyandiamide and formaldehyde, melami/, R1, Off □, 8 □
Gaga Yutsueyu. 1) Ammonium salts, condensates of dicyandiamide and polyalkylene tetraamine or their ammonium salts, 2) cationized dicyanthia-based resins consisting of urea/formaldehyde polycondensates of cyandiamide, etc. can.

The cationic dicyandiamide resin in the present invention further reacts and insolubilizes water-soluble dyes for inkjet use (direct dyes, basic dyes, acid dyes, etc.) when they are incorporated into the acetoacetylated 4-lipinyl alcohol. It has a function.

In general, it is said that a larger amount of cationic dicyandiamide resin as a dye fixing agent is preferable in order to prevent ink from flowing out due to water and to increase the strength of the coating film against water. In other words, dyes such as direct dyes are applied to chromosomes (
In order to firmly dye the pigments (fibers, textiles, paper), etc. or the pigments in the coating layer, dye fixatives such as borian, dicyandiamide, and preethyleneimine are added to 00. Usually 7 for wt%
It is necessary to use more than wt%.

However, according to the present invention, the cationic dicyandiamide resin added to the coating layer can exhibit excellent water resistance even in a smaller amount than is normally required. Furthermore, it is rather advantageous in the present invention to use a smaller amount of the cationic reef-disiac iP-based resin, since this tends to reduce photofading of the ink on the recording surface.

That is, the weight ratio of the cationic dicyandiamide resin used in the present invention to the pigment is preferably O0/~ to 100 parts of the pigment, which is more effective K'' a O,!~.

On the other hand, the pigment used in the present invention has an average particle diameter of 3 to
It is 73 μm. Above average particle diameter Id% Cou
ltsr El@ctronlcs Inc, e 匍=
r-Luther counter model TAI.

If the average particle diameter is smaller than 3μ, it becomes difficult for the ink dots to spread on the placement paper, while if a pigment with a size larger than /Sμ is used, the shape of the ink dots on the placement paper becomes distorted, which is not preferable in either case. .

In order to achieve the object of the present invention, it is preferable that the pigment particles used have as sharp a particle size distribution as possible and have uniform particle diameters.

As the material used in the present invention, any material commonly used in the past can be used without any problem as long as it has the above-mentioned average particle diameter.

For example, synthetic silicic acid, aluminum hydroxide, talc, heavy grade calcium, magnesium carbonate, calcium sulfate, barium sulfate, titanium oxide, clay, magnesium sulfate, quick earth, zinc oxide, satin white, aluminum silicate, alumina, synthetic Aluminum silicate, magnesium silicate, magnesium oxide, magnesium hydroxide, synthetic hydrotalnite, synthetic magnesium silicate,
No white products such as synthetic calcium silicate, sodium aluminate, potassium aluminate, magnesium hydroxide, zeolite, etc. 41! Examples include white organic pigments containing resins such as pigments, ion exchange resin powders, urea resin powders, urea formalin powders, and polystyrene resins.

In addition, the shape of the pigment used in the present invention is preferably spherical, but is not necessarily limited to this.The specific surface area of the pigment particles does not need to be particularly limited in carrying out the present invention; It does not need to be a porous material.

The above ingredients can be used alone or in a mixture of two or more types. Furthermore, a coagulation aid (for example, oxidates, carbonates, hydroxides, etc. of sodium, aluminum, potassium, magnesium, etc.) may be used in combination with the above pigment.

In the present invention, the pigment has a pigment:binder weight ratio of 10:/~io:io°, preferably 11-J:,
It is preferable to use the range of 10:/J to 10Nia.

If the weight of the pigment on the nozzle binder exceeds the above range, it is undesirable because the strength of the coating will decrease. This is undesirable because it makes it difficult for the pigments to be absorbed into the coating film.In short, it is preferable to firmly bind the pigments together using a relatively small amount of binder in order to obtain the recording sheet of the present invention.

The recording sheet of the present invention can be obtained by preparing a paint consisting of a binder, a dye fixing agent, and a pigment in advance, and applying the resulting paint onto a support such as paper.

The above-mentioned paint according to the present invention can be prepared by adding, for example, a binder made of acetoacetylated polyvinyl alcohol and a cationic dicyandiamide-based resin to the pigment slurry, while taking the same precautions in handling the cationized water-bathable binder and anionic substances that are commonly used. It can be prepared by a method of mixing while stirring sequentially.

Further, the above-mentioned coating material can be applied onto the surface of the support by various commonly used methods. Examples include coaters such as air doctors, blades, bars, rods, rolls, gravure coaters, and spray coaters.

The amount of paint applied is,! Usually 5~-〇i', preferably 7~l
It can be set as t/i. If the coating amount is too small, the ink absorption will be insufficient, while if it is too large, the ink absorption capacity will be high but it will be difficult to control the spread of the ink dots, so either case is not preferable.

The support used in the present invention is usually 1% paper.

However, for example, cloth, nonwoven fabric, synthetic paper, etc. can also be used as the support without any problem.

The sheet for inkjet recording of the present invention obtained in this way has a diameter of O of the ink dots printed on the sheet.
is approximately j, 4d-1s, Od (where d is the aperture of the nozzle), especially 1jf or approximately, ? ,A
d-,! -, , Ii' (controlled to have a size within the range of l).

If 0 is less than 3.4 t d, the area of the dots will be small, and the dots will not appear continuous to the naked eye, resulting in a loss of naturalness, which is not preferable.

Furthermore, if D exceeds 6.0d, dots will stick together, resulting in poor resolution and dull colors, which is not preferable.

Hereinafter, the present invention will be explained in more detail with reference to Examples. However, the present invention is not limited to these examples.

In addition, parts and percentages shown in the examples mean heavy responsibility parts and heavy responsibility percentages, respectively.

In addition, various physical properties in the examples were measured by the following methods.

Inkjet recording device: On-dead type inkjet recording device with an ink dot diameter (nozzle diameter) tOμ and an ink dot density of 23 dots and 10.

(D is 100x Lux for printed black, magenta, and cyan (measured at Let it be O.

Shape of ink dot: Observe the shape of the ink dot on the recording sheet with a 100x Louie magnification. If the shape is close to a perfect circle, mark it as O, and if the peripheral part is like a burr, mark it as X.

Ink absorption evaluation: ・If the ink dot is overprinted using the above ink dot device and the ink is pressed from the top to the other surface within a few seconds and there is no transfer to the other surface, it is rated O. ◇Water resistance of the coating film: The recording sheet is 20 211H in water at ℃
Dip the coated surface in w@t state with your finger.0 If the coating film (coating layer) cannot be easily removed, mark it as O.0 Fixability of ink dye: Place the printed area in water at 20℃. After soaking for 7 hours and drying, Macbeth Densitometer RO! for yellow and magenta! It is measured in r/l and a residual rate of 0% or more is defined as O.

Lightfastness: The printed recording sheet was measured on a Quedemeter 1″゛″1゛″−″1 Macbeth #Degometer Rr)! Measured at /Hiro, and 60% or more of residual filtration is defined as O.

Example/Synthetic aluminum silicate Ekumda θ% Sos2 average particle diameter 9μ
m Co-partial acetoacetylation/livinyl alcohol 10% solution (Nippon Gosei Co., Ltd. Co9-Cefheimer 2 cooo)
200 parts cationic dicyandiamide formalin condensate 37% solution (Neofix FY manufactured by NICCA Chemical ■)
/3 parts water
The above acetoacetylated polyvinyl alcohol, cationic dicyancyamide formalin condensate, and water were sequentially added to a slurry of synthetic aluminum silicate dispersed using a bead-type disperser with stirring to prepare a paint. After screening this paint, apply it with a Meyer par.t/Of/rr
? The inkjet recording sheet was obtained by coating A IIf/m' on high-quality paper and drying, followed by suit 4-calendering.

The sheet is printed on an on-demand inkjet printer (
After peta printing was performed using an ink dot diameter gOμm), various physical properties were measured.The results obtained are shown in Table 1.

Comparative Example/~3 Instead of 1cetoacetylated 4-rivinyl alcohol, 70% solution of 4-rivinyl alcohol (@Kuraray Popal 10
! r) C Comparative Example 1), 10% polyacrylamide solution (
Comparative Example 2) and 330 parts of a 7% hydroxyethyl cellulose aqueous solution (Comparative Example) were used to prepare recording sheets in the same manner as in Example 1, and various physical properties were measured. It is shown in Table 1.

Example: Calcium carbonate average particle diameter 5 μm 100
Part acetoacetylated polyvinyl alcohol 10% solution 250 parts Cationic dicyandiamide formalin condensate 37% solution 73 parts Water /
! A coating material was prepared in the same manner as in Example except that the upper part of the θ portion was included, and a recording sheet was prepared.The spread of ink dots (D) obtained by 0 printing was 3.20 μm. Other physical properties obtained through measurements are shown in Table 1.

Example 3 In place of 250 parts of synthetic aluminum silicate, 200 parts of a 200% slurry of a mixture (mixing ratio /:/) of synthetic aluminum silicate with an average particle size of 70 μm and synthetic aluminum silicate (mixing ratio /:/) was used. A coating material was prepared in the same manner as in Example 1, and a recording sheet was produced.

The spread of ink dots obtained by printing (0) is 3
It was 1.0 μm. The measurement results of other physical properties are shown in Table 1.

Example DA A coating material was prepared in the same manner as in Example 1, except that synthetic aluminum silicate having an average particle diameter of 3 μm was used in place of calcium carbonate, and a recording sheet was produced. Expansion of ink dots obtained by printing! D (D) is Goo θμm
Met. The measurement results of other physical properties are shown in Table 1.

Comparative Examples t~6 Instead of calcium carbonate with an average particle diameter of 5 μm in Example =, calcium carbonate with an average particle diameter of 3 μm (Comparative Example), synthetic aluminum silicate with an average particle diameter of 20 μm (Comparative Example, average particle diameter) A coating material was prepared in the same manner as in Example 1, except that 25 μm synthetic aluminum silicate (Comparative Example 6) was used, and recording sheets were produced. The measurement results of various physical properties obtained for these recording sheets are as follows. It is shown in Table 1.

Example! Example/Cationic dicyandiamide formalin condensate #) K Cationic dicyandiamide modified melamine adduct (Sun Chemical ■Ii Workofix! 2g) Joya
A recording sheet was prepared in the same manner as in Example 1 except that the liquid/co part was used. The measurement results of various physical properties of the obtained recording sheet are shown in Table 1. Comparative Example 7sg Example/ The cationic dicyanoamide form I77a of
**. 0. Yokaaoy! $+): r-, vy < i l-based dye fixing agent (manufactured by Nippon Shokubai Kagaku ■) spx-Ol Co B3
A recording sheet was prepared in the same manner as in Example 1, except that 76 parts of 0% liquid (Comparative Example 7) and 76 parts of cationic polyethyleneimine dye fixer 5px-0/2B 30% liquid Jf part (Comparative Example 1r) were used. did. The recording sheets obtained and the measurement results of various physical properties are shown in Table 1.

〔Effect of the invention〕

The inkjet recording sheet of the present invention has all of the following excellent properties (see Table 1).
0 (1) Expansion of ink dots! >(0/d) is relatively large, about ≠~, and the shape of the ink dot is approximately a perfect circle.

(2) There are no color stains on the ink dots, and there are no color stains. The ink absorbency is good even if the sheets are overprinted.

(3) Water resistance of the coating film (coating W4) and ink fixability and light resistance (excellent).

Claims (3)

[Claims] (1) An inkjet recording sheet in which a coating layer consisting of a binder, a dye fixing agent, and a pigment is provided on at least one side of a support, (a) the binder consists of acetoacetylated polyvinyl alcohol; (b) An inkjet recording sheet characterized in that the dye fixing agent is a cationic dicyandiamide resin, and (c) the pigment has an average particle diameter of 5 to 15 μm. (2) The ink jet recording sheet according to claim 1, wherein the binder contains 15 to 100% acetoacetylated polyvinyl alcohol. (3) Claims 1 or 2, wherein the diameter D of the ink dots printed on the inkjet recording sheet is in the range of 3.4d to 6.0d (where d is the aperture of the nozzle). Inkjet recording sheet as described.