JP2002331743A - Ink jet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording sheet, of which the discoloration after long term storage of an ink jet recording sheet printed in full colors, especially the discoloration due to fading in the case that a phthalocyanine-based dye is employed as a cyan ink dye is remarkably reduced. SOLUTION: In the ink jet recording sheet, on which a recording image is formed with a water-base ink, at least one kind of compound selected from compounds represented by general formula (1) is included in the recording sheet. In formula (1), R1 and R2 each represent a 1-4C alkyl group or a 1-4C alkoxyl group, n represents an integer of from 1 through 6 and 1 and m each represent 0 or an integer of from 1 through 3.

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 for forming a recorded image using an aqueous ink, and more particularly, to a print density of an image printed in full color on the ink jet recording sheet is high. The present invention relates to an ink-jet recording sheet which does not discolor during long-term storage, which is a disadvantage of a conventional ink-jet recording sheet, while maintaining a characteristic of excellent ink absorbability.

[0002]

2. Description of the Related Art An ink-jet recording system in which an aqueous ink is ejected from a fine nozzle to a recording medium to form an image,
Terminal printers, facsimile machines, plotters, form printing, etc., because there is little noise during recording, color printing is easy, high-speed recording is possible, and it is cheaper than other printing devices. Widely used in On the other hand, the rapid spread of printers, high definition and high speed,
Furthermore, with the advent of digital cameras, there has been a demand for advanced characteristics on the recording body side. That is, there is a strong demand for a recording medium having excellent absorbency, recording density, water resistance, and storability and having image quality and storability comparable to silver halide type photographs.

[0003] In order to respond to such demands, there have been many proposals regarding sheets provided with an ink receiving layer mainly comprising a pigment and an adhesive on a support. For example, a coating layer composed of amorphous silica and a polymer binder (JP-A-55-51583, JP-A-57-157786 and JP-A-62-158084), and a coating layer having an ink-adsorbing pigment such as zeolite ( JP-A-56-14417
No. 2), a coating layer composed of finely divided silicic acid and a water-soluble resin (Japanese Patent Application Laid-Open No. 56-148583), and a coating layer having a porous cationic alumina hydrate (Japanese Patent Application Laid-Open No. Sho 60-2).
No. 32990) is provided on a support.

Further, from the viewpoint of improving the water resistance of printing, cationic polymers (Japanese Patent Application Laid-Open Nos.
JP-A-49990, JP-A-61-125878), a method of incorporating a basic latex (JP-A-57-36692) and the like into an ink receiving layer have been proposed.

Further, from the viewpoint of improving the storage stability of printing, a method of adding at least one of a metal oxide such as phosphotungstic acid, phosphomolybdic acid, chromic chloride, a metal chloride or tannic acid (particularly). Kaisho 57-8798
No. 7), a method of adding an antioxidant such as a hindered phenol (JP-A-57-74192), and a method of adding a hindered amine (JP-A-61-1465).
No. 91), a method of adding an ultraviolet absorber such as a benzophenone type, a benzotriazole type or a phenylsalicylic acid type (JP-A-57-74193, 57-879).
Nos. 88 and 63-222885), a method of adding a thiourea-based compound (JP-A-61-163886), addition of a specific mercapto compound such as 2-mercaptobenzothiazole and 2-mercaptobenzimidazole. (Japanese Unexamined Patent Publication (Kokai) No. 7-178279), a method of adding a dithiocarbamate, a thiuram salt, a thiocyanate or a thiocyanate.
No. 82) has been proposed.

However, full-color ink-jet recorded images formed using these techniques are still unaffected by discoloration during long-term storage, especially when a phthalocyanine dye is used as a dye for cyan ink, due to its fading. It was not enough.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for discoloring a long-term storage, which is a disadvantage of a conventional ink jet recording sheet, especially when a full-color image is printed on the ink jet recording sheet. The present invention relates to an ink jet recording sheet in which when a phthalocyanine dye is used as a dye, discoloration due to the fading is significantly reduced.

[0008]

According to the present invention, there is provided an ink jet recording sheet for forming a recorded image using an aqueous ink, wherein the recording sheet contains at least one compound selected from the compounds represented by the general formula (1). It is an ink jet recording sheet characterized by being subjected to the following.

Embedded image [Wherein, R ₁ and R ₂ each represent a C ₁ -C ₄ alkyl group or a C ₁ -C ₄ alkoxyl group, n represents an integer of 1-6, and l and m represent 0 or 1-3, respectively. Indicates an integer. The present invention provides a compound represented by the general formula (1):
Ink jet recording characterized by containing at least one selected from a homopolymer of a diallylamine compound represented by the general formula (2) and a copolymer of an ethylenically unsaturated compound copolymerizable with the general formula (2). Pertaining to a sheet for use.

Embedded image [Wherein, R ₃ and R ₄ each represent a hydrogen atom or a methyl group, and HX represents an acid. The present invention provides a compound represented by the general formula (1):
-Bis (phenylthio) butane or 1,6-bis (phenylthio) hexane; The present invention relates to an inkjet recording sheet provided with a cast gloss layer on the inkjet recording sheet. The present invention relates to an ink jet recording sheet having an ink receiving layer subjected to a cast treatment. The present invention relates to an inkjet recording sheet in which a cyan dye used in an aqueous ink is a phthalocyanine dye.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have proposed, in an ink jet recording sheet for forming a recorded image using an aqueous ink, at least one compound selected from the compounds represented by the general formula (1) in the recording sheet. By containing, when printed in full color on the ink jet recording sheet, discoloration during long-term storage which was a disadvantage of the conventional ink jet recording sheet, especially when using a phthalocyanine dye as a dye for cyan ink The present inventors have found that an ink jet recording sheet with significantly reduced discoloration due to the fading can be obtained, and have completed the present invention.

[0010]

Embedded image [Wherein, R ₁ and R ₂ each represent a C ₁ -C ₄ alkyl group or a C ₁ -C ₄ alkoxyl group, n represents an integer of 1-6, and l and m represent 0 or 1-3, respectively. Indicates an integer. ]

Specific examples of the compound represented by the general formula (1) include 1,2-bis (phenylthio) ethane,
3-bis (phenylthio) propane, 1,4-bis (phenylthio) butane, 1,5-bis (phenylthio) pentane, 1,6-bis (phenylthio) hexane,
2-bis (4-methylphenylthio) ethane, 1,4-
Bis (4-methylphenylthio) butane, 1,6-bis (4-methylphenylthio) hexane, 1-phenylthio-2- (4-methylphenylthio) ethane, 1-phenylthio-4- (4-methylphenyl Thio) butane, 1
-Phenylthio-6- (4-methylphenylthio) hexane, 1,4-bis (2-methylphenylthio) butane, 1,4-bis (3-methylphenylthio) butane,
1,4-bis (3,4-dimethylphenylthio) butane, 1,4-bis (2,3,4-trimethylphenylthio) butane, 1,4-bis (4-ethylphenylthio)
Butane, 1,4-bis (4-t-butylphenylthio)
Butane, 1,2-bis (4-methoxyphenylthio) ethane, 1,4-bis (4-methoxyphenylthio) butane, 1,6-bis (4-methoxyphenylthio) hexane, 1,4-bis ( 4-isopropoxyphenylthio)
Butane, 1-phenylthio-4- (4-methoxyphenylthio) butane, 1-phenylthio-4- (4-isopropoxyphenylthio) butane, and the like.

Among these compounds, 1,4-bis (phenylthio) butane and 1,6-bis (phenylthio) hexane are particularly preferably used because they have a particularly high discoloration preventing effect.

In the present invention, the compound represented by the general formula (2)
By containing at least one selected from a homopolymer of a diallylamine-based compound represented by the formula (I) and a copolymer of an ethylenically unsaturated compound copolymerizable with the general formula (2), a high synergistic effect can be achieved for preventing discoloration. Is recognized.

[0014]

Embedded image [In the formula, R ₃ and R ₄ each represent a hydrogen atom or a methyl group, and HX represents an acid. ]

The acid represented by HX in the general formula (2) may be either an inorganic acid or an organic acid. Examples of the inorganic acid include hydrochloric acid,
Sulfuric acid, nitric acid, phosphoric acid, pyrophosphoric acid, metaphosphoric acid and the like, and organic acids include formic acid, acetic acid, propionic acid, methanesulfonic acid and p-toluenesulfonic acid. Among these acids, hydrochloric acid and sulfuric acid are particularly effective in preventing discoloration and are preferably used.

Examples of the homopolymer and copolymer of the diallylamine compound represented by the general formula (2) include polydiallylamine hydrochloride, polydiallylamine sulfate, diallylamine hydrochloride / acrylamide copolymer, and diallylamine sulfate / acrylamide copolymer. Polymers and the like can be used, and by using these, not only water resistance is improved, but also synergistic effect in preventing discoloration.

When a full-color ink-jet recorded image undergoes discoloration during long-term storage, particularly when a phthalocyanine dye is used as a dye for cyan ink, the discoloration accompanying the fading is remarkable because the cyan dye having a phthalocyanine skeleton is caused by gas in air. In particular, it is considered that the gas is easily and selectively oxidized by a highly oxidizing gas such as ozone.

Although it is not clear why the compound represented by the general formula (1) found this time was particularly effective in preventing discoloration, the compound itself represented by the general formula (1) itself is oxidized such as ozone. It is considered that the cyan dye is oxidized before being oxidized because it is easily oxidized by a strong gas, and as a result, oxidation of the cyan dye is prevented.

Another feature of the present invention is that the compound formed by oxidizing the compound represented by the general formula (1) is colorless, and does not cause a problem such as yellowing of the background.

The content of the compound represented by the general formula (1) in the ink jet recording sheet is 0.1
４4 g / m ² , preferably about 0.2-2 g / m ² . By the way, if the amount is less than 0.1 g / m ² , the effect of improving storage stability becomes insufficient, and if it is more than 4 g / m ² , the image quality is deteriorated, which is not preferable.

When a homopolymer and a copolymer of the compound represented by the general formula (2) are used in combination, the content thereof is generally 1 to 100 parts by weight, preferably 5 to 50 parts by weight based on 100 parts by weight of the pigment. Adjusted in range. If the compounding amount is small, it is difficult to obtain the effects of improving the printing water resistance, the printing density, and the like, and if it is large, the printing density is reduced and the image is easily blurred.

Examples of a method for preparing an ink jet recording sheet containing the compound represented by the general formula (1) include a method of applying or impregnating a base paper with a coating solution containing a specific compound by a size press or the like in a paper making process. An ink-receiving layer coating solution obtained by mixing an ink-absorbing pigment, an adhesive, and a specific compound onto a support such as paper (acid paper, neutral paper), synthetic paper, plastic film, or non-woven fabric. To form an ink receiving layer by applying and drying, a method of applying a coating liquid containing a specific compound on an ink receiving layer composed of a pigment, an adhesive, and a specific polymer.

Among them, a method of including the above-mentioned specific compound in the ink receiving layer is preferable because it is more effective in preventing discoloration of an image.

The compound represented by the general formula (1) is
For example, water is used as a dispersion medium and finely pulverized by a stirring / pulverizer such as a ball mill, an attritor, a sand mill, and a colloid mill, and then used.

As the support of the ink jet recording paper, paper (acid paper, neutral paper), synthetic paper, plastic film, nonwoven fabric or plastic film bonded to coated paper or woodfree paper via an adhesive, Alternatively, a material obtained by laminating plastic on paper is used. Examples of such a plastic film include films of polyester, polypropylene, nylon and the like.

Examples of the pigment to be contained in the ink receiving layer include zeolite, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium oxide, zinc oxide,
Zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, amorphous silica, aluminum hydroxide, alumina,
Examples include alumina hydrate, aluminosilicate, lithopone, and urea-formalin resin filler. These may be used alone or in combination of two or more.

Among these, amorphous silica, alumina and alumina hydrate are preferably used because of their excellent ink absorbability.

The amount of the pigment used in the ink receiving layer is as follows.
About 20 to 90% by weight based on the solid content of the ink receiving layer,
Preferably, it is about 30 to 80% by weight. If the content exceeds 90% by weight, the coating strength of the ink receiving layer decreases, and if the content is less than 20% by weight, the ink absorbency decreases, the ink drying property after recording becomes insufficient, and the image quality may deteriorate. is there.

In the present invention, it is also possible to use, as the cationic polymer, a polymer which dissociates when dissolved or emulsified in water to exhibit cationicity. As such a cationic polymer, for example,
Polydiallyldimethylammonium chloride, diallyldimethylammonium chloride / acrylamide copolymer, diallyldimethylammonium chloride / sulfur dioxide copolymer, polyallylamine hydrochloride, N-vinylacrylamidine hydrochloride / acrylamide copolymer, dialkylamine / epichloro Hydrin addition polymer, polyamide polyamine epichlorohydrin polymer,
Dicyandiamide / formalin polycondensate, polyethylene polyamine / dicyandiamide polycondensate, polyethyleneimine hydrochloride, poly (meth) acryloyloxyalkyldialkylamine hydrochloride, (meth) acryloyloxyalkyldialkylamine hydrochloride / acrylamide copolymer, poly ( (Meth) acryloyloxyalkyltrialkylammonium chloride, (meth) acryloyloxyalkyltrialkylammonium chloride / acrylamide copolymer, poly (meth) acrylamidoalkyldialkylamine hydrochloride, (meth) acrylamidoalkyldialkylamine hydrochloride / acrylamide copolymer Coalescence, poly (meth) acrylamidoalkyltrialkylammonium chloride, (meth) acrylamidoalkyltrialkyl Le Kill chloride-acrylamide copolymer, and the like.

In the ink receiving layer, adhesives such as starch derivatives such as oxidized starch and etherified starch, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, casein, gelatin, soy protein,
Complete (partial) saponified polyvinyl alcohol, silicon-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, styrene-maleic anhydride copolymer salt, styrene-butadiene latex, acrylic latex, polyester polyurethane latex, vinyl acetate An aqueous adhesive such as latex or an organic solvent-soluble resin such as polymethyl methacrylate, a polyurethane resin, an unsaturated polyester resin, a vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, and an alkyd resin is used alone or in combination of two or more. These adhesives are generally used in an amount of 1 to 20 parts by weight based on 100 parts by weight of the pigment.
It is used in an amount of about 0 parts by weight, preferably about 10 to 100 parts by weight.

Further, a pigment dispersant,
Thickeners, crosslinkers, fluidity modifiers, defoamers, defoamers, release agents, foaming agents, penetrants, coloring dyes, coloring pigments, fluorescent brighteners, preservatives, anti-foaming agents, waterproofing Agents and the like can be appropriately added.

The ink receiving layer is prepared by applying a coating solution for the ink receiving layer to a bar coater, blade coater, air knife coater, or the like.
It is formed by applying and drying a coating method such as a gravure coater, a die coater, and a curtain coater on at least one surface of the support so that the coated amount after drying is about ² to 30 g / m ² . Incidentally, if the coating amount is less than 2 g / m ² , the recorded image quality is reduced, and if it is more than 30 g / m ² , the coating film strength may be reduced.

After the ink receiving layer is formed, it is possible to impart a surface smoothness between the roll nips under pressure using, for example, a super calender or a gloss calender for the purpose of imparting a high gloss.

Further, by providing a gloss developing layer on the ink receiving layer and performing a casting treatment, or by directly casting the ink receiving layer, an ink jet recording sheet having a higher surface gloss can be obtained. Casting methods include a wet method, a gelling method, and a rewet method. In the wet method, while the glossy layer coated on the base paper is in a wet state, the glossy layer is pressed against the heated mirror drum surface to perform a high gloss finish. In the gelling method, while the glossy layer coated on the base paper is in a wet state, the glossy layer is brought into contact with a gelling agent bath, and the gelled glossy layer is pressed against a heating drum surface. This is to perform high gloss finish. The rewet method is
After the wet glossy layer is once dried and brought into contact with the wetting liquid again, it is pressed against the surface of the heating drum to perform a high gloss finish.

Further, a protective layer may be provided on the back surface of the support,
It is of course possible to provide an intermediate layer between the support and the recording layer, and various known techniques in the field of manufacturing a sheet for ink jet recording can be added.

The aqueous ink for forming a recorded image is a recording liquid comprising a colorant, a liquid medium, and other additives. Examples of the coloring agent include various water-soluble dyes such as direct dyes, acid dyes, and reactive dyes. As the liquid medium of the aqueous ink, there is water alone or a combination of water and a water-soluble organic solvent. Examples of the water-soluble organic solvent include monohydric alcohols such as ethyl alcohol and isopropyl alcohol, polyhydric alcohols such as ethylene glycol, diethylene glycol, polyethylene glycol, and glycerin, triethylene glycol monomethyl ether, triethylin, triethylene glycol monomethyl ether, and triethylene. And lower alkyl ethers of polyhydric alcohols such as glycol monoethyl ether. Further, examples of the additives include a pH adjuster, a metal sequestering agent, an anticorrosive, a viscosity adjuster, a surface tension adjuster, a surfactant, and a rust inhibitor.

[0037]

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

(Preparation of dispersion of 1,4-bis (phenylthio) butane) 1,4-bis (phenylthio) butane 1
00 parts, sulfone group-modified polyvinyl alcohol (trade name: Goselan L-3266, manufactured by Nippon Synthetic Chemical Co., Ltd.) 5
Parts, a small amount of a surfactant, an antifoaming agent, and water, and a composition having a solid content of 20% was pulverized with a sand grinder until the average particle diameter became 0.5 μm to obtain a dispersion.

(Preparation of coating liquid for ink receiving layer) 100 parts of synthetic amorphous silica (trade name: Fine Seal X60, manufactured by Tokuyama Corporation), silicon-modified polyvinyl alcohol (trade name: R-1130, Co., Ltd.) 25% 10% aqueous solution of Kuraray)
0 parts, diallylamine hydrochloride / acrylamide copolymer (trade name: Sumireze Resin 1001, Sumitomo Chemical Co., Ltd.)
Coating solution for ink receiving layer having a solid content concentration of 15%, consisting of 75 parts of a 40% aqueous solution of the above, 50 parts of a 20% dispersion of 1,4-bis (phenylthio) butane and a small amount of an antifoaming agent, a dispersant and water I got

(Preparation of Ink-Jet Recording Sheet) 6
After providing the ink-receiving layer by coating and drying a wire bar such that the 12 g / m ² of the ink-receiving layer coating solution on a solids to fine paper of 5 g / m ^2, and super calendering the inkjet recording Sheet was created.

Examples 2 to 4 Example 1 was repeated except that the following compound was used in place of 1,4-bis (phenylthio) butane.
In the same manner as in the above, an ink jet recording sheet was prepared. Example 2: 1,6-bis (phenylthio) hexane Example 3: 1,4-bis (4-methylphenylthio) butane Example 4: 1,2-bis (phenylthio) ethane

Example 5 In Example 1, diallylamine hydrochloride / acrylamide copolymer (trade name: Sumireze Resin 1001,
In the same manner as in Example 1 except that a polydiallyldimethylammonium chloride / acrylamide copolymer (trade name: PAS-J-81, manufactured by Nitto Boseki Co., Ltd.) was used instead of Sumitomo Chemical Co., Ltd.). To prepare an ink jet recording sheet.

Example 6 (Preparation of coating liquid for glossy layer) Composite of styrene-2-methylhexyl acrylate copolymer and colloidal silica having a glass transition point of 75 ° C. 40:60) 100 parts, 5 parts of an alkyl vinyl ether / maleic acid derivative copolymer as a thickening / dispersing agent, and 3 parts of lecithin as a releasing agent, solid content concentration 3
A 0% glossy layer coating liquid was obtained. (Preparation of Ink-Jet Recording Sheet) The coating liquid for the ink-receiving layer of Example 1 was coated on a high-quality paper of 65 g / m ² at a solid content of 1%.
After coating and drying with a wire bar to provide ² g / m ² and providing an ink receiving layer, applying a gloss developing layer coating liquid, and immediately pressing against a mirror surface drum having a surface temperature of 85 ° C.,
After drying, release was performed to prepare a gloss type inkjet recording sheet having a gloss layer. At this time, the coating amount of the gloss layer was 8 g / m ² in solid content.

Comparative Example 1 An ink jet recording sheet was prepared in the same manner as in Example 1 except that 1,4-bis (phenylthio) butane was not used.

Comparative Example 2 Ink jet recording was carried out in the same manner as in Example 1 except that dilauryl 3,3'-thiodipropionate was used in place of 1,4-bis (phenylthio) butane. Created a sheet.

Comparative Example 3 The procedure of Example 1 was repeated, except that 2,6-di-tert-butyl-p-cresol was used instead of 1,4-bis (phenylthio) butane. An ink jet recording sheet was prepared.

Comparative Example 4 An ink jet recording sheet was prepared in the same manner as in Example 6, except that 1,4-bis (phenylthio) butane was not used.

Using the Epson ink jet printer PM-800C, the ink jet recording sheets obtained in the examples and the comparative examples were solid printed with mixed black and cyan inks using a mixture of cyan, magenta, and yellow, and an ISO-400 image (" High-definition color digital standard image data ISO / JIS-SCI
D ", p13, image name: portrait, published by The Japan Planning Association, and the following evaluations were performed. The results are shown in Table 1. In PM-800C, a phthalocyanine dye is used as a cyan dye.

[Print Density] The density of the solid printing portion of the mixed black and cyan inks of the mixed colors of cyan, magenta and yellow was measured using a Macbeth densitometer (model: RD-914,
Macbeth).

[Ozone resistance] Ozone resistance, which has a high correlation with long-term storage stability, was evaluated. Solid printing of mixed black and cyan inks using a mixture of cyan, magenta, and yellow inks and images of ISO-400 were performed using an ozone concentration of 10 p.
pm container for 12 hours. In the case of solid printing, the Macbeth density after the test was measured, and the image remaining rate was calculated by the following equation. On the other hand, in the case of an image, the degree of discoloration was visually observed and evaluated. Image residual rate (%) = [(density after processing) / (density before processing)] × 100 (Evaluation criteria) ：: No discoloration is observed. ○: Discoloration is slightly observed, but there is no practical problem. X: Discoloration is remarkable and there is a problem in practical use.

[0051]

[Table 1]

[0052]

As is clear from Table 1, the ink jet recording sheet of the present invention has a high print density of the image, has very little discoloration of the image even when exposed to ozone gas, and has a long-term storage property. It was a recording sheet excellent in quality.

Claims (6)

[Claims] 1. An ink jet recording sheet for forming a recorded image using an aqueous ink, characterized in that the recording sheet contains at least one compound selected from the compounds represented by the general formula (1). Recording sheet. Embedded image [Wherein, R ₁ and R ₂ each represent a C ₁ -C ₄ alkyl group or a C ₁ -C ₄ alkoxyl group, n represents an integer of 1-6, and l and m represent 0 or 1-3, respectively. Indicates an integer. ] 2. A method according to claim 1, wherein the homopolymer of the diallylamine compound represented by the general formula (2) and a copolymer of an ethylenically unsaturated compound copolymerizable with the general formula (2) are contained. The inkjet recording sheet according to claim 1, wherein: Embedded image [Wherein, R ₃ and R ₄ each represent a hydrogen atom or a methyl group, and HX represents an acid. ] 3. The compound represented by the general formula (1) is:
The ink-jet recording sheet according to claim 1, which is 4-bis (phenylthio) butane or 1,6-bis (phenylthio) hexane. 4. The ink jet recording sheet according to claim 1, wherein a gloss layer cast is provided on the ink jet recording sheet. 5. The ink jet recording sheet according to claim 1, wherein the ink jet recording sheet has an ink receiving layer subjected to a cast treatment. 6. The ink jet recording sheet according to claim 1, wherein the cyan dye used in the aqueous ink is a phthalocyanine dye.