JP2694042B2 - Manufacturing method of recording material - Google Patents

Description

The present invention relates to a method for producing a recording material suitable for use in ink jet recording and the like, and more specifically, as in the case of forming a full color image with high density. A recording material that has excellent ink absorbency, blocking resistance, beading resistance, long-term storage stability at high temperatures, and high translucency as required even when a large amount of ink adheres per unit area. Manufacturing method.

[Conventional technology]

The ink jet recording method is attracting attention as a recording method that can generate high-speed printing and multi-color printing with less noise.

The recording material used in this inkjet recording method is conventionally referred to as ordinary paper or inkjet recording paper, which is a recording material provided with a porous ink receiving layer on a substrate, and a translucent material for OHP. Recording materials have been used.

2. Description of the Related Art In recent years, with the improvement in performance of an ink jet recording apparatus such as high-speed recording and multi-color recording, recording materials have been required to have higher and wider characteristics.

In particular, as a translucent recording material for inkjet, 1) excellent translucency, 2) excellent ink absorption, 3) high dot optical density (OD), and Full dot
High OD, 4) Excellent blocking resistance, 5) No beading (beading is a phenomenon in which a large amount of ink is unevenly distributed on the surface of the ink receiving layer, causing so-called “density unevenness”). ), Etc. must be satisfied at the same time. In particular, the beading phenomenon is particularly noticeable when a droplet having a large ink capacity is used, when the ejection frequency of the droplet is high, or when multicolor droplets are used as in color recording. In that case, it becomes difficult to obtain a highly precise image.

In addition, blocking resistance is the same as when a recording head with multiple ink ejection ports (nozzles) is used or when a full-color image is formed with multiple color inks, a large amount of ink is deposited on the recording material at the same time. Required when dripping.
That is, the resin of the ink receiving layer that has absorbed a large amount of ink swells and dissolves in the ink, develops tackiness, and sticks to paper, plastic film, and the like. This phenomenon is called a blocking phenomenon, and the property of not blocking even when a large amount of ink is applied to the recording material is called blocking resistance.

Conventionally, various studies have been made to satisfy the above functions,
Although it has achieved some results, a recording material that satisfies all of these performance requirements has not yet been known.

Conventionally, recording materials for inkjet using a water-based ink during recording include albumin, gelatin, casein, starch, cationic starch, gum arabic, hydrophilic natural resins such as sodium alginate, polyvinyl alcohol, cationized polyvinyl alcohol, polyamide, polyacrylamide. , Polyvinylpyrrolidone, quaternized polyvinylpyrrolidone, poly (N-vinyl-3-methylpyrrolidone), polyvinylimidazole, polyallylamine, polyallylamine hydrochloride, polyethyleneimine, polyvinylpyridylium halide, melamine resin, polyurethane, carboxymethylcellulose, Water solubility of hydroxyethyl cellulose, cationized hydroxyethyl cellulose, hydroxypropyl cellulose, polyester, sodium polyacrylate, etc. Properly were often one or more hydrophilic synthetic resin material is used as desired. However, in the case of the ink receiving layer made of at least one of the hydrophilic or water-soluble resins, a beading phenomenon occurs when a large amount of ink is deposited, and it is difficult to obtain a high-definition image.

In order to suppress the beading, JP-A-57-1731
Japanese Patent Laid-Open No. 94 discloses that water-absorbent resin particles are used in combination in the receiving layer. In this case, beading is apparently suppressed, but according to fine observation with an optical microscope,
Most of the ink is absorbed by the water-absorbent resin particles,
As a result, the optical density of the image in the entire ink receiving layer becomes low.

 Next, blocking resistance will be described.

JP-A-59-174382 discloses a recording material containing a condensation product of D-sorbitol and benzaldehyde.
The condensation product is used in an amount of 5 to 200 parts by weight based on parts by weight.

In the materials used in the above publication, the condensation product is 70 parts by weight per 100 parts by weight of the polymer material used in the ink receiving layer.
The recording material in an amount of at least parts by weight has good blocking resistance in the printed area.

However, since the water-soluble resin used for the recording material and the condensation product have poor compatibility, when the recording material is stored for a long period of time or stored under high temperature and high humidity, the condensation product is It may be precipitated from the ink receiving layer to be whitened, or the periphery of the printed portion may be whitened by water or an alcohol or polyhydric alcohol which is preferably used in the water-based ink.

As described above, in a system in which a water-soluble resin is used to enhance ink absorbability and a water-insoluble compound is used in combination to enhance blocking resistance, compatibility, particularly long-term compatibility, becomes important.

That is, it has been difficult in the prior art to achieve both ink absorbency, blocking resistance, beading resistance, and storage stability.

[Problems to be solved by the invention]

Therefore, an object of the present invention is to provide a method for producing a recording material which is excellent in ink absorption, blocking resistance, and beading resistance even when a large amount of ink is applied at high density.

Further, the object of the present invention is to provide a method for producing a recording material which has the above-mentioned recording characteristics stably even after long-term storage and storage at high temperature, and has excellent translucency when used for OHP and the like. To do.

Another object of the present invention is to provide a method for producing a recording material which is excellent in storage stability of a printed matter for a long period of time or high temperature and high humidity.

[Means for solving the problem]

The above object can be achieved by the following means of the present invention.
That is, the present invention relates to a method for producing a recording material having a substrate and an ink receiving layer directly formed on the substrate, and at least two components containing a water-soluble polymer compound and a water-insoluble low-molecular compound. And, a heating solution containing a solvent that is a good solvent for one component and a poor solvent for the other component is directly applied to the substrate, and then the solvent in the solution is dried and removed. The gist is a method of manufacturing a characteristic recording material.

[Action]

The recording material according to the present invention has a base material and an ink receiving layer formed directly on the base material.

As the substrate, any of transparent and non-translucent substrates can be used, but as the transparent substrate, for example, polyester resin, diacetate resin, triacetate resin, acrylic resin, Examples thereof include films or plates of polycarbonate resin, polyvinyl chloride resin, polyimide resin and the like, glass and the like.

In the present invention, the ink receiving layer formed directly on the upper surface of the substrate is a combination of a water-soluble polymer compound and a water-insoluble low-molecular compound, and the water-soluble polymer compound absorbs the aqueous ink. The beading is prevented, and the water-insoluble low molecular weight compound improves the blocking resistance.

Here, in the present invention, a water-soluble compound is a compound having a solubility of 10 g or more in 100 g of pure water at 25 ° C., and a water-insoluble compound is defined as a compound of less than 1 g under the same conditions. As a method of measuring the solubility, an excess amount of a solute (here, an organic compound) is dissolved in a solvent (here, pure water) at 25 ° C. and completely saturated at that temperature. Next, a certain amount of this solution is accurately measured, the solvent is completely distilled off, and then the rest is measured. Then weigh the solute in 100 g of the solution, add the solvent until the solute is completely dissolved, and add 100 g of the solvent.
There is a method to find the number of grams of solute in it.

The water-soluble polymer compound used in the present invention has a molecular weight of 5,000 or more. More preferably, it indicates a molecular weight of 10,000 or more. The molecular weight can be measured by GPC (gel permeation chromatography).

The water-soluble organic polymer compound, albumin, zeramine, casein, starch, gum arabic, natural resin such as sodium alginate, carboxymethyl cellulose,
Hydroxyethyl cellulose, hydroxypropyl cellulose, polyacrylamide, polyethyleneimine, polyvinylpyrrolidone, poly (N-vinyl-3-methylpyrrolidone), polyvinylimidazole, polyvinyl alcohol, polyethylene oxide, sodium polyacrylate, polyamide, polyacrylamide, polyallylamine hydrochloride Examples thereof include salts and synthetic resins such as polyvinylpyridinium halide.

As the water-insoluble low molecular weight compound, a condensate of D-sorbitol and an aromatic aldehyde, 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5 , 5] undecane, 2,2-bis (4′-oxyphenyl) propane, the diacetate compound, and the like.

In the present invention, in addition to the above compounds, a resin soluble in a general organic solvent may be used together in order to adjust the hydrophilicity of the ink receiving layer. For example, N-methoxymethylated nylon (type 8 nylon), polyvinyl butyral, poly 2-hydroxyethyl methacrylate, polymethyl methacrylate, polystyrene, phenol resin, epoxy resin, polyvinyl chloride, polyester, polyurethane and the like can be preferably used. Alternatively, when an acidic dye or a direct dye is used in the water-based ink, a cationic resin can be used to prevent the dye from bleeding and leaching after recording. In this case, bleeding of the dye in the recorded matter under high temperature and high humidity can be suppressed. Examples of the polymer compound that can be used for this purpose include cationized polyvinyl alcohol, cationized hydroxyethyl cellulose, and cationized monomer-containing acrylic resin.

In the present invention, the ink receiving layer is formed by combining the above-mentioned organic compounds having different water solubility.

Therefore, the present invention provides ink absorbability with a water-soluble organic compound.

That is, the ink receiving layer is formed by combining two or more kinds of organic compounds having different water solubility so that the absorption efficiency of pure water is double or more. Here, the absorption capacity for pure water is that the desired ink receiving layer is immersed in pure water at 25 ° C. for 1 minute, and then the ink receiving layer containing water is hung down at 25 ° C./50% RH for 5 minutes. It represents the amount of water retained after naturally adhering water was dropped.

The compounding ratio varies depending on the compound to be combined, but generally, the ratio of the water-soluble polymer compound to the water-insoluble low molecular weight organic compound is preferably 2: 8 to 8: 2.

In the present invention, a combination of a water-soluble polymer compound and a water-insoluble low molecular weight compound is particularly preferable from the viewpoint of blocking resistance.

A system using a water-soluble low molecular weight compound has a drawback that when the water or the water-based ink adheres to the ink receiving layer, the low molecular weight compound is eluted, and the blocking resistance is lowered.

Further, a combination of a water-insoluble polymer compound and a water-insoluble low molecular weight compound has excellent blocking resistance, but on the other hand, since there is no material having an affinity for the water-based ink, the ink absorbability is significantly lowered.

Among the water-soluble polymer compounds, polyvinylpyrrolidone is a water-soluble resin excellent in ink absorbability.

On the other hand, as the water-insoluble low molecular weight compound, the above-mentioned compounds can be used in the present invention, but a condensate of sorbitol and an aromatic aldehyde is the most preferable water-insoluble compound. Explaining the condensate in detail below, since D-form is easily available as sorbitol, the D-sorbitol system is easy to use.

Examples of aromatic aldehydes include benzaldehyde, halogenated benzaldehyde, tolualdehyde, salicylaldehyde, cinnamaldehyde, naphtholaldehyde, and the like.The condensation products of these compounds and sorbitol are used alone or in combination. To be done.

In particular, the condensation product of D-sorbitol and benzaldehyde is easily available, and the gelation effect is high, which is the most preferable.

The condensation product of D-sorbitol and benzaldehyde used in the present invention is synthesized by the condensation reaction of D-sorbitol and benzaldehyde, and the molar ratio of D-sorbitol and benzaldecht is 1: 1, 1: 2 and 1: 3. However, it is preferable to use the one of 1: 2 or 1: 3, and the one of 1: 2 is the most suitable.

Condensation products of D-sorbitol and benzaldehyde in a molar ratio of 1: 2 are dibenzylidene sorbitol (trade name: Gelol D, manufactured by Shin Nippon Rika Co., Ltd.) and 1:
The three are called tribenzylidene sorbitol (trade name: Gelol T, manufactured by Shin Nippon Rika Co., Ltd.).

Dibenzylidene sorbitol is a chemically neutral compound and shows solubility (about 15 g / 100 g solvent) in solvents such as N-methylpyrrolidone, N, N-dimethylformamide, and dimethylsulfoxide, but most solvents, For example, water, ethyl alcohol, isopropyl alcohol, ethylene glycol, glycerin, diethylene glycol,
It has low solubility in benzyl alcohol, ethyl cellosolve, tetrahydrofuran, dioxane, cyclohexylamine, aniline, pyridine and the like.

In the present invention, it has been found that the absorption capacity can be adjusted not only by the material and the combination of the materials but also by the manufacturing method.

The production method of the present invention, the above two compounds are dissolved in a solvent that is a poor solvent for one component and a good solvent for the other component by heating at 50 to 150 ° C., It is a method of coating and drying.

Here, the good solvent referred to in the present invention means that the solubility of an organic compound in a desired solvent at 25 ° C. is 10 g or more, while the poor solvent means that the solubility is less than 1 g.

As the solvent preferably used in the present invention, any solvent can be used as long as it satisfies the above conditions, but water, ethyl alcohol, propyl alcohol, butyl alcohol, 2-ethylhexanol, penzyl alcohol, ethylene glycol, diethylene glycol, methyl cellosolve. , Ethyl cellosolve, butyl cellosolve, dioxane, morpholine, pyridine, dichlorohexylamine, alinine, nitrobenzene, sulfolane, tetrahydrofuran, formamide, methyl ethyl ketone, dioctyl phthalate and the like are preferably used.

As a material used for the ink receiving layer, it is particularly preferable to use polyvinylpyrrolidone and a condensation product of sorbitol and benzaldehyde in combination.

Used as these solvents are sulfolane, tetrahydrofuran, formamide, methyl ethyl ketone,
Dioctyl phthalate, dioctyl phthalate, ethyl alcohol, isopropyl alcohol, butyl alcohol, 2-ethylhexanol, benzyl alcohol, diethylene glycol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, dioxane, morpholine, pyridine, cyclohexylamine, aniline, nitrobenzene and the like can be mentioned. .

As a method for forming the ink receiving layer, the coating liquid is applied onto a substrate by a known method such as a roll coating method, a rod bar coating method, a spray coating method, an air knife coating method, and then dried. The method is preferred.

Generally, the thickness of the ink receiving layer is 1 to 100 μm, preferably 2 to 30 μm.

The recording material of the aspect formed as described above is a translucent recording material having sufficient translucency when a transparent base material is used.

Sufficient translucency in the present invention means that the haze of the recording material is
It means 50% or less, preferably 20% or less.

If the haze is 50% or less, it is possible to project the recorded image on the screen by OHP and observe the details of the recorded image in detail.

Further, in the present invention, in the recording material of the above-mentioned aspect, an organic or inorganic fine powder is applied to the recording surface of the recording material.
By imparting at a rate of 0.01 to about 1.0 g / m ² , it is possible to further improve the transportability of the obtained recording material in the printer, the blocking resistance during stacking, the fingerprint resistance, and the like.

The present invention has been described above by exemplifying a typical aspect of the recording material according to the present invention, but of course the present invention is not limited to this aspect. In any case,
The ink receiving layer may contain various known additives such as a dispersant, a fluorescent dye, a pH adjuster, an antifoaming agent, a lubricant and a preservative.

The recording material according to the present invention does not necessarily have to be colorless and may be a colored recording material.

The recording material according to the present invention as described above exhibits excellent ink receptivity and gives a recorded image with excellent sharpness.

Therefore, in the recording of full-color images as well as in mono-color, even if inks of different colors overlap and adhere to the same location within a short time, there is no phenomenon of ink bleeding or bleeding, and beading and bleeding occur. A clear recorded image with no high resolution can be obtained.

Hereinafter, the method of the present invention will be described in more detail with reference to Examples. In the text, "part" or "%" is based on weight unless otherwise specified.

For the recording materials obtained in Examples and Comparative Examples, the following 4
Bubble jet recording head (ejection droplet volume 24pl, head density 16pel / mm, single color maximum ejection amount 6nl / m) that ejects ink by foaming ink using one kind of ink
Inkjet recording was carried out using a recording apparatus having m ² , maximum number of color superimpositions of 3 and ejection frequency of 4 kHz.

Yellow ink (composition) CI Acid Yellow 23 3% by weight Diethylene glycol 15% by weight Water 82% by weight Cyan ink (composition) CI Direct Blue 86 3% by weight Diethylene glycol 15% by weight Water 82% by weight Magenta ink (composition) CI Acid Red 35 3 % By weight Diethylene glycol 15% by weight Water 82% by weight Black ink (composition) CI direct black 193% by weight Diethylene glycol 15% by weight Water 82% by weight The measurement of each evaluation item in Table 1 was performed according to the following method.

(1) Haze was measured using a direct-reading haze meter (manufactured by Toyo Seiki Seisakusho) having an optical system conforming to JIS K 6714.

(2) Ink absorbency is based on warm air (100%) on the recording material after recording full dots of three colors of yellow, cyan, and magenta.
When the recorded image was touched with a finger at a temperature of 1 ° C. and a wind speed of 1 m / sec for 10 seconds, it was determined whether the ink was taken into the ink receiving layer and did not adhere to the finger.し な い indicates no attachment, X indicates attachment, and Δ indicates the middle.

(3) With respect to beading resistance, after recording full dots of three colors of yellow, cyan and magenta, they are visually judged, and those with no beading are marked with ◯, those with beading are marked with x, and the middle thereof is set. It was set as Δ.

(4) Blocking resistance is as follows. Warm air (10%) is applied to the recording material after recording full dots of three colors of yellow, cyan and magenta.
When the polyethylene terephthalate film was laminated on the recorded image at 0 ° C. and a wind speed of 1 m / sec, 10 sec) at a pressure of 40 g / cm ² , it was judged whether or not the film could be easily peeled off. The case where it could be easily peeled was marked with ◯, the case where considerable force was required for peeling was marked with x, and the middle thereof was marked with Δ.

(5) Haze of film after storage at high temperature and high humidity is 35 ℃ / 90% R
The film was used after standing at H for 10 hours. It measured using the same haze meter as (1).

(6) The transparency of the printed matter after storage at high temperature and high humidity is 35 ° C after recording full dots of three colors of yellow, cyan and magenta.
The printed matter was observed after being left at / 90% RH for 100 hours.

If no whitening is observed around the printed area, ○, OH
△, OHP if whitening occurs to the extent that it is not projected on P
The ones that were projected in and the whitened part turned black were marked with x.

(7) The haze of the film after storage at high temperature was sealed at 60 ° C / 9 in an aluminum-laminated polyethylene bag of the recording material.
The haze after storage for 200 hours under 0% RH was measured by the method (1).

(8) Absorption capacity of pure water: The desired recording material is gently immersed in pure water at 20 ° C for 1 minute, and then the ink receiving layer containing water is suspended at 20 ° C / 50% RH for 5 minutes to naturally absorb water. After cutting, the amount of water absorbed and retained was measured.

The value obtained by measuring the amount of pure water absorbed with respect to the own weight of the ink receiving layer was used.

(9) Regarding the solubility in pure water, 20 g of a desired solute (organic compound) was mixed with 100 g of pure water, and the mixture was stirred overnight.

Then, dissolve or disperse the liquid into a filter paper made by Toyo Roshi
After filtering with No. 5C, the weight of the insoluble matter remaining on the filter paper was measured to determine the solubility.

Example 1 A polyethylene terephthalate film (trade name: Lumirror T-100, manufactured by Toray Industries, Inc.) having a thickness of 100 μm was used as a substrate, and the following coating composition A was heated to 85 ° C. and dried. It was coated by a bar coater method so as to have a thickness of 12 μm, and dried at 140 ° C. for 5 minutes.

Coating composition A 1,3,2,4-dibenzylidene D-sorbitol (water-insoluble low-molecular compound, trade name Gelol D manufactured by Shin Nippon Rika Co., Ltd., solubility in pure water less than 1 g) 40 parts Polyvinylpyrrolidone (water-soluble Resin, GAF product name PVP K-90, molecular weight 100,000 or more, solubility in pure water 10 g or more) 50 parts Cationic resin (water-soluble resin, Soken Chemical Co., Ltd. product name
PQ-10, solubility in pure water of 10 g or more) 10 parts Methyl Cellosolve 1500 parts Example 2 The following coating composition B was heated to 95 ° C.

Coating composition B Polyvinylpyrrolidone (water-soluble resin, same as above) 70 parts Bisphenol A (water-insoluble low molecular weight compound, solubility in pure water less than 1 g) 30 parts Water 2000 parts Carry out the above coating composition After drying on the same polyethylene terephthalate film as in Example 1, it was coated by a bar coater method so as to have a thickness of 12 μm, and dried at 140 ° C. for 5 minutes to obtain a product of the present invention.

Comparative Example 1 Polyvinyl alcohol (water-soluble resin, Kuraray PV
A-217, degree of polymerization 1700, saponified product of 88%, solubility in pure water of 10 g or more) 100 parts is dissolved in 900 parts of water and dried on the same polyethylene terephthalate film as in Example 1 to 12 μm.
Was applied by a bar coater method and dried at 140 ° C. for 5 minutes.

Comparative Example Polyvinyl butyral (water-insoluble resin, Sekisui Chemical Co., Ltd., trade name S-REC BH-3, solubility in pure water
100 g (less than 1 g) was dissolved in 900 parts of ethyl cellosolve. After drying on the same polyethylene terephthalate film as in Example 1, it was coated by a bar coater method so that the thickness became 12 μm, and dried at 140 ° C. for 5 minutes.

Comparative Example 3 The same polyethylene terephthalate film as in Example 1 was used, and the following coating composition C was dried on this film.
Coated by the bar coater method to 12 μm, 14
It was dried under the condition of 0 ° C. for 5 minutes.

Coating composition C 1,3,2,4-dibenzylidene D-sorbitol (water-insoluble low molecular weight compound, same as above) 40 parts polyvinylpyrrolidone (water-soluble resin, same as above)
50 parts Cationic resin (water-soluble resin, same as above) 10 parts DMF 500 parts Comparative Example 4 Further DM in the receiving layer of the recording material (comparative product) obtained in Comparative Example 3.
After applying 100 parts of F to a thickness of 100 μm, it was allowed to stand at room temperature for 20 seconds, and then DMF was dried at 140 ° C. for 5 minutes.

Comparative Example 5 The same procedure as in Example 1 was carried out except that the coating composition A was applied at 25 ° C without heating to 85 ° C.

[Effects of the Invention] As described above, by applying an appropriate heating solvent to the ink receiving layer in which materials having different compatibility are mixed and drying again, excellent ink absorption is achieved even after long-term storage or storage at high temperature. It was possible to obtain a recording material having stable recording properties such as resistance, batting resistance and blocking resistance, and excellent translucency when the substrate was transparent.

Further, by this manufacturing method, it is possible to obtain a recording material which is excellent in long-term storage of the printed matter or storage stability under high temperature and high humidity and is excellent in translucency.

Claims (5)

(57) [Claims] 1. A method for producing a recording material having a base material and an ink receiving layer formed directly on the base material, wherein at least two components containing a water-soluble polymer compound and a water-insoluble low-molecular compound are provided. And, it is a good solvent for one component,
A method for producing a recording material, characterized in that a heating solution containing a solvent that is a poor solvent for the other component is directly applied to the substrate, and then the solvent in the solution is dried and removed. 2. The method for producing a recording material according to claim 1, wherein the water-soluble polymer compound is polyvinylpyrrolidone, and the water-insoluble low-molecular compound is a condensation product of sorbitol and an aromatic aldehyde. 3. The method for producing a recording material according to claim 1, wherein the solvent is water or methyl cellosolve. 4. The method for producing a recording material according to claim 1, wherein the recording material is translucent. 5. The method for producing a recording material according to claim 1, wherein the recording material is for inkjet recording.