JPS60171190A - Ink jet recording paper - Google Patents

Abstract

PURPOSE:To provide the titled recording paper suitable for ink jet recording, particularly, multicolor ink jet recording, wherein a coated layer comprising a specified amount of a specified nonionic surface active agent in an aqueous coating material is provided on a base. CONSTITUTION:The objective recording paper comprises a coated layer and a base, the coated layer consisting of a composition which comprises solid component A, of an aqueous coating material and a nonionic surface active agent B having an HLB value of 4-10, preferably, a polyethylene oxide derivative, a PP derivative, a polyhydric alcohol derivative, a higher alcohol-ethylene oxide adduct or an alkylphenol-ethylene oxide adduct in an amount of 1-10wt% to component A.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording paper, and more particularly to an inkjet recording paper which is composed of a base material and a coating layer and is particularly suitable for multicolor inkjet recording.

``In recent years, there has been a demand for multicolor image recording, and various color printers are being developed, and at the same time, there is an urgent need to develop recording paper suitable for color printers. Among color printers, the inkjet recording method has an excellent position as an information device that can easily produce multiple colors.

There are currently three main types of inkjet recording methods: charge type, on-demand type, and bubble/queue type. The principle behind ink being attached to a fixed point on a support and drying to become an ink dot (hereinafter referred to as a dot) is the same.

Color inkjet kikama mainly uses black, magenta,
It uses water-based inks of four colors, cyan and yellow, and consists of dots that correspond to halftone dots in offset printing to create multiple colors. iiiigI! Color tones are simply produced by overlapping colors on dots in the same position, but it is also known to create intermediate tones by making the ink droplets even finer, making the dots even smaller, and forming halftone dots using the matrix.

In general, commercially available medium-quality paper with a surface size is often used as inkjet recording paper, but due to the above-mentioned recording mechanism, ink droplets adhering to the paper surface are quickly absorbed into the paper layer. It is required to have a property that does not smear when touched immediately after printing, and a property that allows the dots to spread appropriately on the paper surface to form a dark, easy-to-read print. Color printers use multiple jet guns at the same time to deposit all ink of two or more colors on a single point on the paper to perform multicolor recording, so they have better ink absorption than conventional single-color inkjet recording paper. It is necessary to use paper of good quality.

On the market, it is difficult to achieve a balance between these two properties with medium-quality paper, and it is difficult to obtain images with excellent hue, brightness, and chroma. As a means to solve these problems, a recording paper has been proposed in which a coating layer consisting of an inorganic pigment and a binder is provided on the surface of the base paper (Japanese Patent Application Laid-open No. 107879/1983).

In general coated paper, if a sufficient amount of binder is added to maintain the surface strength for normal printing, the ink absorbency is poor and the paper is not suitable for color inkjet recording.

The present inventors applied a paint made by adding various surfactants to a water-based paint consisting of an inorganic pigment and a binder to a base material,
As a result of extensive research into its ink absorption properties,
By adding a specific amount of a specific nonionic surfactant to a commonly used water-based paint, it maintains the physical properties of normal coated paper and increases ink absorption, resulting in inkjet printing with excellent hue, brightness, and saturation. The present invention was achieved by discovering that recording paper can be obtained. The nonionic surfactant specified by the present invention has an HLB value within the range of 4 to 10, and its addition rate is 1 to 10! t%. Adjustment of water-based paint; (The HLB value of a nonionic surfactant used as an antifoaming agent or foam suppressing agent is usually 1.5 to 3, and its addition rate is 1% by weight or less. Also, the HLB value 4~
IO nonionic surfactants are conventionally used as emulsifiers when water is dispersed in oil.

The reason why the effects of the present invention can be obtained by using a nonionic surfactant in the above manner in the present invention is that the nonionic surfactant is in the lipophilic range. When applied to materials, the film-forming properties of the coating layer are suppressed, resulting in an increase in the number of capillaries in the layer, and it is thought that the surface tension of the capillaries is reduced, thereby improving ink absorption.

Note that in an inkjet printer, dots are recorded according to signals, but main scanning is expressed as n dots per sequence. It is said that the diameter of the dot is preferably within the range of the following formula.

%/TP<D<2P (p=4) P: Distance between dot centers Therefore, in the case of a general figure, in the case of 4.7 dots/force, the inkjet dot diameter is 300μ, and in the case of 3.3 dots/plane, the dot diameter is The diameter is 428μ, and the diagonal lines drawn by the printer become continuous straight lines, giving good results. The recording paper of the present invention satisfies this condition.

In addition, color inkjet printers have been miniaturized to 200 μm in size to further improve the accuracy of color gradation.
New devices are being developed with the following objectives in mind, and the present invention can also satisfy these conditions.

Thus, according to the present invention, in an inkjet recording paper comprising a base material and a coating layer, the coating layer is composed of a solid content of an aqueous paint, a nonionic surfactant having an HLB value in the range of 4 to 10, and There is also provided an inkjet recording paper in which the nonionic surfactant is added in an amount of 1 to 10% by weight based on the solid content of the water-based paint.

Hereinafter, the configuration of the present invention will be explained in detail.

Nonionic surfactants are added to water-based paints, but the balance between hydrophilic and hydrophobic groups in their chemical structure, that is, HLB
Value must be in the range 4-10. These are W2O type surfactants that disperse water in oil, and examples include the following.

The value in parentheses is the HLB value.

As polyethylene oxide derivatives, polyethylene glycol laurate monoester (9,s), polyethylene glycol mononisder stearate (8,5), polyethylene glycol oleate monoester (8,4)
), polyethylene glycol laurate diester (6
, 6,9,8), polyethylene glycol stearate diester (5,4°8.5), polyethylene glycol oleate diester (5,3,8,4).

Pluronic type ethylene oxide low molar adducts (5 to 7) and tetronic type ethylene oxide low molar adducts (5 to 7) as polypropylene/derivatives. As a polyhydric alcohol derivative, sorbitan lauric acid monoester (s
, 6) + sorbitan palmitic acid monoester (6,7
), Nrubitai, stearic acid monoester (4,7)
, sorbitan oleate monoester (4,3)l sorbitan stearate monoester ethylene oxide 4
Molar adduct (9,6) l Sorbitan oleic acid monoester ethylene oxide 5 molar adduct (10,0).

Propylene glycol fatty acid ester (4-5).

Diethylene glycol fatty acid ester (5-6).

As a higher alcohol ethylene oxide additive, oleyl alcohol ethylene oxide 2 mole adduct (4,9
) t Matney alcohol ethylene oxide 5 mole adduct (9,3). Nonylphenol ethylene oxide 4 as alkylphenol ethylene oxide additive
Molar adduct (8,9).

When the HL) 3 value is 4 or less, it becomes difficult to emulsify and disperse in water,
As a result, the dispersed particles in the coating layer aggregate and become coarse, making the effects of the present invention astounding. If it is 10 or more, it will be easily dispersed under water pressure, but it will foam during coating and change the viscosity of the coating solution, making coating work difficult, and also cause migration on the surface of the coating layer or within the base paper when drying. This impairs the surface properties and reduces the effect of the present invention. 4 to 7 are preferably used.

The addition rate of the surfactant used in the present invention is 1% relative to the solid content.
% to 10% by weight. In this range, the action of the nonionic surfactant promotes ink absorption regardless of the size of the base paper in contact with the coating layer. If it is less than 1% by weight, it becomes necessary to select the size of the base paper. When the amount is 10% by weight or more, ink bleeding on the surface tends to increase, and manufacturing costs also increase. 3-5 for regular size paper
Weight 1 to % is suitable. The pigment used may be either an inorganic pigment or an organic pigment, but inorganic pigments such as fine silica gel, precipitated calcium carbonate, ground calcium carbonate, kaolinite sauce, and halloysite creni are usually used. Note that the water-based paint may be a clear paint containing no pigment. There are no particular restrictions on adhesives, but modified starch,
Natural adhesives such as oxidized starch, esterified starch, dextrin, carboxymethyl cellulose, hydroxyethyl cellulose, and milk casein; synthetic polymers such as polyvinyl alcohol, styrene-butadiene latex (5BB), methyl methacrylate-butadiene latex, It is preferable to use one or more of acrylic latexes such as acrylic esters and methacrylic esters, and vinyl latexes such as vinyl acetate. These adhesives are usually pigmented
It is added in an amount of 20 to 50 parts by weight per 00 parts by weight. In addition, pigment dispersants, thickeners, waterproofing agents, and the like can all be added as appropriate. Coating is performed using a blade coater, air knife coater, roll coater, gravure coater, etc., and the solid content is 3 to 109/it.

It should be noted that since the coated sheet of the present invention has many capillary tubes, it is not preferable to give it a strong pressure using a super calender, but it is possible to give it a glossy surface by applying a light calender, cross calender, or plush. In some cases, it may be appropriate for the purpose by adding or smoothing. Furthermore, after inkjet recording, it is also effective to laminate a film on the recording surface or overlay a transparent paint to increase color density and gloss and improve aesthetic appearance.

Next, this invention will be fully explained in detail with reference to examples, but the invention is not limited thereto. below,
Parts are parts by weight.

Example 1 Precipitated Calcium Carbonate (PFIZER-Quigl)
Manufactured by er, Albagross 8F, average particle size 0.6 μ) 1
To 0.00 parts, 0.3 parts of sodium polyphosphate and 370 parts of gold were added, and the mixture was stirred and dispersed for 3 hours. To this, a 10% solution of 6.25 parts each of oxidized starch (Nihon Shokuhin Kako, M83800) and polyvinyl alcohol (Denki Kagaku Kogyo, Denka Size A-50) was added as a binder, and styrene-butadiene latex (Sumitomo Naugatac) was added as a binder. 5N307) 7!
12.5 parts of l-solids were added. The total amount of binder was 25 parts. Three parts of Tetronic type ethylene oxide 20e4 additive (Asahi Denka, Tetronic 702, HLB value 6.2) was added to this dispersion and stirred vigorously for 30 minutes. Furthermore, water resistance agent (Sumitomo Chemical, 5Z-6
13) was added to prepare a coating solution. The solid content of the coating liquid was 21 inches, and the viscosity was 35 cp (25°C). The addition rate of the nonionic surfactant was 3% by weight based on the pigment and 2.3% by weight based on the solid content.

Next, high-quality paper (size degree: 20 seconds) with a basis weight of 529/m was coated with an air knife coater, coating amount/(solid content)
51/m" single-sided coated paper was obtained. It was finished with a super calender to obtain inkjet recording paper with a smoothness of 133 seconds and a paper thickness of 74μ. Color printing was performed using this paper using Sharp's Inkjet Color Image Printer Model 700. The print was clear and the ink drying property was good.The printed dot diameter was 300 μm, and the print density was 0.99 as measured with a Macbeth densitometer over the entire petaprint area.

Coated paper with no surfactant added had poor ink drying properties in the same inkjet printer, staining the paper transport roll and staining the paper surface. The printing dot diameter is 1
The print density of 40 μm was too small, and the print density of the peta-printed portion was 0.50 Macbeth density, which was unclear.

Example 2 Amorphous silica (Tabon Chemical, Zeoseal 1000V) 10
0 part was dispersed in 900 parts of water, and as a binder, 12.5 parts of oxidized starch (Nihon Shokuhin Kako, M83800), 25 parts of polyvinyl alcohol (Denka Size A-50, Denki Kagaku Kogyo), and styrene-butadiene latex (
Sumitomo Nogatar Ix, 5N-307) Solid content equivalent: 25
part was added. This dispersion was added to a Pluronic-type ethylene oxide 10-adduct (Asahi Denka, Pluronic L-6).
tHLB value 5.8) was added and stirred vigorously for 30 minutes. Furthermore, water resistance agent (Sumitomo Chemical, 5Z-613) t-3
, 75 parts were added to prepare a coating solution. Solid content of coating liquid 15
．． The viscosity of 4 pieces was 120 cp (25°C).

In addition, the addition rate of nonionic surfactant is 5% by weight based on the pigment.
The solid content was 3% by weight. This liquid has a basis weight of 66 & /
Solid content 611 with Meyer bar coater on rrl high quality paper
/ m coated. As a result of printing on this paper using a Canon color printer A1210, the dot diameter was 420 μm, and the peta print density was 0.7 using a Macbeth densitometer. The drying speed of the ink was rapid and no ink stains were observed, and the shape of the dots was circular and uniform.As a 'fi-0 comparative example, Zollonik L-61 without gold addition had a dot diameter of 250μ.
The peta print density was 0.5, and the ink dried slowly and ink stains occurred.

Example 3 Aluminum hydroxide (Showa Denko, Hisilite H42)
100 parts of dispersant, 0.5 part of sodium xametaphosphate was dispersed in 233 parts of water, and sorbitan oleate monoester (Atlas, USA, span 80, HLB value 4.
3) was added and vigorously stirred. To this solution, the same amounts of oxidized starch, polyvinyl alcohol, and styrene putage/latex as in Example 1 were added, followed by water-resisting agent (1). 25 parts of Rix P9007Y)' (Hl) were added.The solid content of the coating liquid was 26.2 cm, and the viscosity was 15 cp (25°C).-!The addition rate of the nonionic surfactant was 5
The solid content was 2.3% by weight. Using an air knife coater, solids content 1 og7. ．． (Coating T was applied. As a result of printing on this using Sharp's inkjet color image printer model 700, the dot diameter was 280 μm, and the print density was 1.2 μm using a Macbeth densitometer.
．． A clear print of 0 was obtained.

The ink dried well and no ink stains were observed on the paper surface. Similarly, in a comparative example in which Span 80 was not added, the dot diameter was 140μ, and the print density was 0.4 using a Macbeth densitometer.
Because the ink was slow to dry, ink stains occurred and printing could not be continued.

Patent applicant: Mishima Paper Co., Ltd.

Claims (2)

[Claims] (1) In an inkjet recording paper consisting of a base material and a coating layer, the coating layer has a solid content of water-based paint and an HLB value of 4 to 1.
1. An inkjet recording paper comprising a nonionic surfactant in the range of 0.0 to 1.0%, and the addition rate of the nonionic surfactant is 1 to 10% by weight based on the solid content of the aqueous paint. (2) The nonionic surfactant is selected from polyethylene oxide derivatives, polypropylene derivatives, polyhydric alcohol a conductors, quaternary alcohol ethylene oxide additives, or alkylphenol ethylene oxide additives. Claims The inkjet recording paper according to item 1.