JPS58134783A - Recording material - Google Patents

Abstract

PURPOSE:To provide a recording material capable of speedily absorbing an ink and producing dots with small diameters, by providing a coated layer consisting of a collection of a plurality of films which consist of a polymer having a hydrophilic structural part and a hydrophobic structural part and are partitioned from each other by cracks. CONSTITUTION:A polymer which compries 2-40wt%, preferably 25-40wt% of a hydrophilic structural part introduced by an alpha,beta-unsaturated monomer or the like and a hydrophobic structural part introduced by styrene or the like and has a molecular weight of not less than 2,000 is dissolved or dispersed in a solvent to prepare a coating material. The coating material is applied onto a base 1 consisting of a liquid-absorptive porous material such as a paper in an amount of 1-10g/m<2>, and is dried to produce the coated layer 2 in which a plurality of minute scale form films partitioned from each other by irregularly shaped cracks are closely spaced in the manner of two-dimensional arrangement, thereby obtaining the desired recording material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording material (hereinafter also referred to as recording paper) used for recording characters, figures, etc. using a recording liquid.

Conventionally, recording with recording liquid, that is, ink, has been widely performed using, for example, chain marking tools such as pens, pens, and felt-tip pens. Furthermore, recently, an inkjet recording method has also appeared, and recording liquid is used here as well.

Incidentally, this inkjet recording method uses various ink ejection methods (for example, an electrostatic suction method, a method that applies mechanical vibration or displacement to the ink using a piezoelectric element, a method that uses a piezoelectric element to apply mechanical vibration or displacement to the ink, and a method that heats and foams the ink and uses the pressure In this method, ink droplets are formed and some or all of them are attached to a recording material such as paper. .

In this way, when recording using liquid ink, it is generally necessary that the ink does not bleed onto the surface of the recording paper and cause the print to become blurry, and that the ink is applied as quickly as possible after recording. to prevent the paper from drying out and accidentally contaminating the paper surface, and
It is desirable that the coloring matter in the ink is fixed on the paper and does not discolor.

In particular, the above-mentioned inkjet printing system requires: (1) fast absorption of recording liquid (ink) onto recording paper; and (2) fast absorption of ink dots, especially when performing multi-color or full-color recording. Even if there is overlap, make sure that ink that adheres later does not adhere to the front, disrupting the dots, and causing them to flow out. ■ The ink droplets will spread on the recording paper surface, and the diameter of the ink dots will not match the required diameter on the recording paper. ■ The shape of the ink dot must be close to a perfect circle, and the area around it must be smooth; ■ The density of the ink dot must be uniform and the area around the dot must not be blurred. ■ The color of the recording paper must be white. The contrast between the ink dot and the ink dot is large; ■ The color of the ink does not change depending on the type of recording paper; ■ There is little scattering of ink drops around the ink dot; ■ Dimensional variations in the recording paper (e.g., wrinkles, spread) are recorded. It is necessary to satisfy various requirements such as having fewer things before and after. However, in the past, it has been understood that satisfying these demands largely depends on the characteristics of the recording paper used; It is still difficult to find a distribution sheet for Kyohen that meets the various demands of the government. For example, JP-A-52-7434
The processed paper for inkjet recording described in No. 0 is
Although the ink is absorbed quickly, it has the drawbacks that the diameter of the ink dot is large and easily blurs the periphery of the dot, and the dimensional change of the paper after recording is large.

SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to satisfy the problems that the prior art could not solve in the technical field of ridges.

In particular, it is an object of the present invention to provide a high-performance recording material (recording paper) that satisfies almost all the various requirements on ridges in recording using liquid ink using a writing instrument or an inkjet recording method. It is said that

Accordingly, the recording material of the present invention that achieves the above object has the following properties on the base. A coating layer is provided using a paint containing a polymer having both a hydrophilic structural part and a hydrophobic structural part, and this coating layer aggregates a large number of films finely divided by irregularly shaped cracks. It is characterized by being made up of.

Hereinafter, the present invention will be explained in detail with reference to illustrated examples and examples.

First, the configuration of the present invention will be outlined using the schematic diagram of FIG.

In the figure, l is a liquid-absorbing substrate, such as paper,
Made of porous material such as cloth. 2 is a covering layer which receives ink.

This coating layer 2 is basically prepared using a high quality resin paint, but the paint contains a polymer having both a hydrophilic structure part and a hydrophobic structure part as a main component. Ru. Such polymers are mainly polymers of monomers having addition-polymerizable vinyl groups, and hydrophilic structural moieties such as carboxylic acid groups, sulfonic acid groups, and sulfuric acid ester groups are bonded to a predetermined amount of acrylic acid. acids, methacrylic acid, crotonic acid, itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, fumaric acid, fumaric acid monoester, vinyl sulfonic acid, sulfoethyl methacrylate, sulfopropyl methacrylate, sulfonated vinyl naphthalene 7, etc. The α,/-unsaturated heptanomer is used to introduce into the polymer structure.

On the other hand, monomer units for introducing hydrophobic structural moieties include styrene, styrene derivatives, vinylnaphthalene, vinylnaphthalene derivatives, and aliphatic alcohol esters of C-C1 of α,β-ethylenically unsaturated carboxylic acids. Most desirable O In addition to the above-mentioned seven units, for example, acrylonitrile, vinylidene chloride, α, β-ethylenically unsaturated carboxylic acid esters other than those on the ridge, vinyl acetate, vinyl chloride,
Acrylic acid, Methacrylic acid, Hitomi 4 diethyl methacrylate, Hydroxypropyl methacrylate,
Glycidyl methacrylate, N-methylolacrylamide, N1-butoxymethylacrylate, etc. can be used.

By the way, in the present invention, it is necessary to form a salt of the polymer in order to solubilize or disperse the polymer in the solvent of the paint in the form of a colloid. As a partner to form a salt with the above polymer, Na, which is an alkali metal,
In addition, aliphatic amines such as mono-, di- or tri-(ethylamine), mono-, di- or tri-(ethylamine),
Alcoholic compounds such as mono-, di-, or tri-(ethanolamine), di-, di-, or tri-(globanolamine), methylethanolamine, dimethylethanolamine, morpholine, Examples include N-methylmorpholine.

In the above polymer, the ratio of monomer units forming the hydrophilic structural portion is very important.

In other words, when the weight ratio of one monomer unit serving as a hydrophilic structural moiety such as a carboxyl group, sulfonic acid group, or sulfuric acid ester group exceeds approximately 40% by weight, the so-called
The sizing effect is reduced and it adheres to the coating layer 2...! The degree of bleeding of the recording liquid (ink) 1 becomes too large.On the other hand, if the weight ratio of the coating layer 2 becomes less than 2 weight x, the bonding force between the coating layer 2 and the substrate 1 decreases, making it easy to peel off. Therefore, a more preferable ratio of the hydrophilic structure moiety in the above polymer is about 25 to 40% by weight.

In addition, if the molecular weight of this polymer is too low, it will lead to deterioration of film forming properties, so it is desirable to use a polymer with a molecular weight of about 100 ml or more than general KFi. can be manufactured according to the method. For example, by mixing essential monomer components in a predetermined ratio, methods such as solution polymerization, emulsion polymerization, and suspension polymerization (
(using a polymerization regulator if necessary) to synthesize a polymer with a desired molecular weight. Separately, polymers containing acid anhydrides, esters, nitrile groups, hydroxyl groups, etc. are prepared first, and these groups are then subsequently polymerized by hydrolysis, saponification, sulfuric acid esterification, or sulfonation. A method □ in which a carboxyl group or the like is generated during coalescence can also be adopted.

The amine salt etc. may be formed at any time; for example, any method may be used, such as polymerization using an amine salt of the carboxylic acid monomer, or adding an amine etc. after polymerization or after the hydrolysis part O. can also be adopted.

In the present invention, a coating paint is prepared by dissolving or dispersing these polymers alone or in combination in a paint solvent.

Shima: In this case, if the film-forming ability of the polymer is poor,
Other binder resins can also be used in combination. As this α-like resin, any water-soluble or organic solvent-soluble resin can be used. For example, water-soluble resins include polyvinyl alcohol, starch, casein, gum arabic, No. B gelatin, polyacrylamide, carboxymethyl cellulose, sodium polyacrylate, sodium alginate,
Examples of organic solvent-soluble resins include polyvinyl butyral, polyvinyl chloride, polyvinyl acetate, polyatarylonitrile, polymethyl methacrylate, polyvinyl formal, melamine resin, polyamide resin, phenol resin, polycrethane resin, alkyd resin, etc. be.

In addition, examples of the solvent for preparing the paint include water alone, or a mixture of water and a water-soluble organic solvent. Examples of the water-soluble organic solvent include methyl alcohol, ethyl alcohol, and pool igo-7
'lopyl alcohol, n-butyl alcohol, 5e
c-butyl alcohol, tert-phthyl alcohol, igo-butyl alcohol.

Alcohols such as furfuryl alcohol and tetrahydrofurfuryl alcohol; Ketones or keto alcohols such as acetone, methyl ethyl ketone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane;
Esters of ethylene carbonate and propylene carbonate: N,N-dimethylformamide, N,N-
dimethylacetoand, N-methyl-2-pyrrolidone,
Examples include nitrogen-containing solvents such as jetanolamine.

KFi forming the coating layer 2 is generally coated on the substrate 1 in an amount of Ig/- to 10 g/lI/fi by a known method (for example, roll coating method, Rotbar coating method, spray coating method). Apply the above-mentioned material. In addition, in practical terms, it is best to apply about 2 g/- to 5 g/-.

After such a coating layer is provided, the coating layer is dried as soon as possible. In the thus obtained coating layer 2, a part of the region 21 is enlarged approximately 50 times, and as shown in the mostly enlarged view 2L, irregularly shaped cracks 4 (
...Most of these cracks 40 reach the surface of the base 1. ) A large number of fine scale-like films 3 are arranged in close two-dimensional arrangement. The size of one scaly film 3 is not particularly limited, but is approximately 10 μm x 10 μm to several hundred μm x several #
srn is common, and the width of the crack 4 is not limited to the width in the present invention, but usually,
It is said to be about several μm. Incidentally, the individual size and shape of the scale-like film 3, the width of the cracks 40, etc. can be determined by adjusting or controlling the composition or film forming conditions of the above-mentioned paint, and the drying conditions after coating. It can be changed arbitrarily within the above range.

When the ink adheres to the coating layer 2 explained above,
The pigment (for example, dye) in the ink chemically or physically bonds with the polymer constituting the film 3, and is selectively adsorbed and captured by the film 3.

On the other hand, after the solvent in the ink passes through the cracks 4, it is quickly absorbed into the substrate 1. In this way, in the present invention, the pigment in the ink is captured on the outermost surface area of the recording paper, so that the color development is extremely good. Also, the solvent in the ink is
Since it quickly migrates to the underlying substrate through the cracks, an apparent dry layer is quickly obtained on the surface of the recording paper. °・Furthermore, the scaly L-shaped film 3 is particularly effective in preventing ink dots from becoming larger than necessary on the recording paper, having a high #[ of the dots, and preventing blurring around the dots; This is because the pigment in the ink is intensively adsorbed in the area of the film 3. The adsorption ability is mainly determined by the chemical properties (eg, ionicity) of the polymer.

In addition, in the present invention, the area occupied by the scale-like skin II3 in the coating layer 2 is extremely reduced, and on the contrary, the area occupied by the cracks 4 is extremely reduced! Any increase in fliiK is undesirable. That is, in the former case, there is a drawback that the dye capture rate is lowered and the color development and density of the dots are reduced. or,
In the latter case, there are disadvantages such as an increase in the amount of ink transferred to the substrate, causing a so-called ink strike-through phenomenon, and deterioration of the dot shape. Therefore, it is desirable to avoid these aspects in the present invention.

Here, more detailed examples will be described to illustrate the effects of the present invention.

In addition, prior to Examples, synthesis examples of polymers which are the main components according to the present invention and examples of commercially available polymers are illustrated below. (・
...All parts in the synthesis examples are parts by weight. ) *Synthesis Example 1. In a four-piece separable flask equipped with a stirrer, 50 parts of water, 30 parts of isopropyl alcohol, 0.5 part of sodium dotecylbenzenesulfonate, and 0.5 part of ammonium persulfate are mixed and heated to 60°C. Separately, styrene 5
A mixture of 9 parts of acrylic acid, 9 parts of butyl acrylate, and 5 parts of butyl acrylate was placed in a separating funnel and gradually added dropwise over 60 minutes. After the dropwise addition was completed, the temperature was raised to 80°C and the mixture was stirred for 2 hours to carry out polymerization.

The molecular weight of the obtained polymer was approximately 50,000.

Example 20 Into the same flask as in Example 1, 8 parts of methyl methacrylate, 5 parts of styrene, 15 parts of itaconic acid, 1 part of benzoyl peroxide, 1 part of lauryl mercaptan, 50 parts of diacetone alcohol, and 20 parts of ethylene glycol were charged. Polymerize for 6 hours while passing nitrogen gas. The molecule t of the obtained polymer was about 30,000.

A polymer was obtained from the following raw materials in the same manner as in Example 2.

(Molecular weight: Approx. 15,000) (Molecular weight: Approx. 20,000) (Molecular weight: Approx. 30,000) (Molecular weight: Approx. 8,000) Examples of commercially available products ・ a, Naphthalene/sodium sulfonate formalin condensate 1°80, Na 80 ．． Na Product name: Demol N [Kao Atlas ■] b, Diisobutylene-maleic acid copolymer Product name; Demol gP [Kao Atlas ■] C3 Sodium polyacrylate Product name: Nobuco Santol [San Nopco ■] d, Poly Ammonium acrylate product name: Nopcosanto RFA [San Nopco ■] C, sodium polymethacrylate product name: Brimar 850 [Rohm & Haas ■] f, styrene/-maleic acid copolymer (monoester ammonium salt) product name: 8MA resin 1440H [Alcochemical ■] g, PEG Product name; Macrogol 150G [NOF ■] h, PEG-PPG block polymer Product name: Uniloop 4QDP-50B [NOF ■] Example 1 Polymer obtained in Synthesis Example 1 (ioo parts by weight) and water (150 parts by weight) were sufficiently stirred and mixed to obtain a slurry.

The slurry was applied to one side of five sheets of base paper (weighing 60 g/I) so that the dry solid content was approximately 4 g/-.

Next, these were dried under the following conditions and recorded paper sample I
-V was created.

*Drying conditions Sample I...Natural drying sample by leaving...Sample 1 in an oven (60℃) for 2 hours.
... Samples were heated in hot air at 90°C for 30 minutes... Samples were heated in hot air at 110°C for 2 seconds. The surface condition of each sample was examined using an electron microscope (X2).
QO) and shown in FIGS. 2 to 6.

The results of a comparative study of the characteristics in inkjet recording of each sample thus obtained are summarized in Table IK below. In addition, in Table 1 below, the dot density was measured using a Sakura microdensitometer PDM-5 (Konishi Roku Photo Industry Co., Ltd. #) with a slit width of 30μ in width and 30μ in height, and a slit width in the X-axis direction. - The speed ratio of the sample feeding speed to the chart feeding speed #ltl■/5lIc is the result of measurement at a magnification of 100 times.

The dot diameter was determined by measuring the diameter of the printed dot using a stereomicroscope. Also, the fixing time can be determined by placing a rubber roller a certain distance away from the inkjet head used and changing the paper feed speed by varying the pressure until the ink dots contact the rubber roller. The time taken from the time an ink dot was generated until the ink stopped adhering to the roller was measured using the same device.

Further, the ink ejection opening diameter (orifice diameter) of the inkjet arrangement cover used here was 5071, and the ink used had the following composition.

Ink physical properties: Viscosity [3.8 cps (measured with Tokyo Needle! 11m1E type rotational viscometer) Surface tension 52°4°/'' (measured with a hanging plate type surface tension meter manufactured by Kyoichi Kaji) Table 1 (Note 1) Number of ink dots placed in the same places (Note 2); Evaluation criteria ◎... Good for non-wealth ○... Good Δ... Generally good × ...Poor Example 2 The polymer obtained in Synthesis Example 3 (100 parts by weight), water (110 parts by weight), and ethanol (50 parts by weight) were sufficiently stirred and mixed to prepare a slurry.

This slurry was applied to the surface of a base paper having a basis weight of 65 g/WI so that the dry solid content was 4 g/l/1, and was dried with hot air at 180° C. for several seconds to prepare a recording paper.

When an electron micrograph was taken of the surface of this coating layer, a photograph equivalent to that shown in FIG. 6 was obtained.

Further, when inkjet recording was performed on this paper in the same manner as in Example 1, the results were similar to those of Sample V in Example 1.

Example 3 After thoroughly stirring and mixing the polymer obtained in Synthesis Example 6 (80 parts by weight), polyvinyl alcohol (20 parts by weight), and water (150 parts by weight) to create a slurry, the slurry was prepared as in Example 2. I carried out the same procedure and obtained the same result.

Example 4.5 Inkjet recording was performed on the same sample as Sample V obtained in Example 1 using the inks shown in Table 2 below in the same manner as in Example 1, and the results were as shown in Table 2 below. That's right.

Table 2 In addition, in the column of ink composition, the numerical value within 0 minus the number of parts is shown, and all other numerical values and symbols, : symbols, etc. are based on Example 1.

1! m9116. 1 Full color recording was performed using the same sample as Sample V of Example 1 using cyan-magenta, yellow, and black inks, and the fixing time, dot density, and dot diameter were all the same as in Example 1. In addition, we were able to reproduce full-color photographs with extremely clear colors and good color reproducibility.

Example 7 Printing was done with a commercially available Mannenjo on the paper arranged in the same manner as in Example 2.
There is no smudging, the absorption of ink and ri is fast, and the handwriting is very clean. : In this case, the recording liquid (ink) attached to the ridge is quickly absorbed into the inside of the -1-, and if different colored recording liquid overlaps in the same place within a short time. There is no phenomenon of the recording liquid flowing out or oozing out even when it is attached to the ink, and the color development of 4 inks is good. We provide a recording material particularly suitable for multi-color infusiera recording, which can be recorded at high speeds.

No. 0. ! Jyu, *-eqo composition overview □ theory. 2 to 6 are all diagrams showing electron microscope photographs of the surface of recording paper.

In the figure, 1 is the base, 2 is the M1 covering layer, 3 is the scale-like coating,
4 is a crack.

4 Applicant: Canon Co., Ltd. jノ”,,Kl is

Claims (1)

[Claims] A coating layer is provided on the substrate using a paint containing a polymer having both a hydrophilic structural part and a hydrophobic structural part, and this coating layer is made up of nine films finely divided by irregularly shaped cracks. A recording material characterized by: