JP2005343150A - Multicolor pressure-sensitive duplicate paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide multicolor pressure-sensitive duplicate paper of which the visual difference in a developed color tone, and the developed color tone and visual difference in this tone of a green color showing the resistance to light after one-day exposure to sunlight, are large. <P>SOLUTION: The multicolor pressure-sensitive duplicate paper is constituted by combining a transfer sheet obtained by a method wherein the ink of microcapsules including an electron-donating color developing agent forming an image of a color tone being different, when developed, from that of another electron-donating color developing agent included in a microcapsule layer which includes this color developing agent and is provided on the whole surface of a substrate is printed locally on the microcapsule layer, with an accepting sheet provided with a layer containing an electron-accepting developer which develops the electron-donating color developing agent included in the microcapsules in the microcapsule layer and the electron-donating color developing agent included in the microcapsules in the ink, in reaction with these two electron-donating color developing agents. The electron-donating color developing agent included in the microcapsules contained in the ink is expressed by general formula 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to multicolor pressure-sensitive copying paper.

  A combination of an electron-donating color former such as crystal violet lactone or benzoyl leucomethylene blue and an electron-accepting color developer such as activated clay, phenol-formaldehyde condensate or polyvalent metal salt of aromatic carboxylic acid, or nickel carboxylate The principle of coloring by the reaction of various chromogenic substances such as a combination of a salt with N, N'-dibenzyl-di-thio-oxamide, a metal salt such as an organophosphate iron salt and lauryl gallate and a ligand compound. The pressure sensitive copying sheets used are well known. Generally, such a pressure-sensitive copying sheet supports a microcapsule (hereinafter simply referred to as “capsule”) containing a chromogenic material prepared by a method such as a phase separation method, an interfacial polymerization method, or an in-situ polymerization method. An upper sheet coated on the substrate, a lower sheet coated with another chromogen material that reacts with the chromogen material to develop the chromogen material on a support, the capsule and the chromogen material. A medium-use sheet coated on different surfaces of a support is used in combination as appropriate.

  Usually, the capsule layer of these pressure-sensitive copying sheets is formed by applying a water-based capsule coating liquid to a support using a large-sized coating machine or a non-aqueous capsule ink using a printing machine. However, both methods are not necessarily the most suitable manufacturing method because a multi-colored and pressure-sensitive copying sheet with good color developability is obtained.

  In other words, the application with a coating machine such as an air knife coater has a feature that a sufficient amount of capsules can be supplied to the support, so that a pressure-sensitive copying sheet with good color development can be obtained. Therefore, inevitably, only the pressure-sensitive copying sheet having a single color tone can be obtained on the entire surface of the sheet. Therefore, when obtaining a pressure-sensitive copying sheet capable of developing multiple colors, there is a problem that it is not suitable.

  On the other hand, in printing by a printing press, the capsule ink can be appropriately printed on the necessary part of the support, and therefore, by using two or more kinds of capsule inks that contain a chromogenic substance that forms a color image with different colors as a core substance. There is a feature that a multicolor pressure-sensitive copying sheet having partially different color tones can be obtained. However, it is a weak point that the amount of capsules that can be applied even if the ink concentration is increased as much as possible in the normal printing method cannot be applied as much as the amount applied by a coating machine. For this reason, there is a drawback that the pressure-sensitive copying sheet has poor color development.

Patent Document 1 discloses an image having a color tone different from that of the chromogenic material when color is formed on the layer of the sheet formed by providing a microcapsule layer including the chromogenic material on the entire surface using a coating machine. A transfer sheet obtained by locally printing a microcapsule ink containing another chromogen material, and the other colorant material that reacts with the chromogen material and develops the color chromogen material. The invention relates to a pressure-sensitive copying sheet characterized by combining a receiving sheet provided with a chromogenic substance-containing layer. However, the pressure-sensitive copying sheet obtained by the embodiment is included in the color tone of the chromogen substance contained in the microcapsule constituting the microcapsule layer and the chromogen substance of the receiving sheet and in the microcapsule in ink. The difference in color tone between the chromogen material and the chromogen material of the receiving sheet was not necessarily sufficient due to black and blue.
Japanese Patent No. 2597655

  In the present invention, a multicolor pressure-sensitive copying paper having excellent color developability, and the electron-donating color former contained in the microcapsule constituting the microcapsule layer in the multicolor pressure-sensitive copying paper and the layer provided in the receiving sheet The difference between the color tone produced by the reaction with the electron-accepting developer and the color tone produced by the reaction between the electron-donating color developer contained in the microcapsules in the ink and the electron-accepting developer is black-blue. A larger green-blue system was used. However, an electron-donating color former having a green color tone with an electron-accepting developer is extremely inferior in light resistance. It is an object of the present invention to provide a multicolor pressure-sensitive copying paper having a color tone with an electron-accepting developer that is excellent in light resistance of a color tone image among green electron-donating color formers.

  In the present invention, a microcapsule layer containing microcapsules encapsulating an electron-donating color former is provided on the entire surface of the support, and the electrons encapsulated in the microcapsule layer when the color is developed on the microcapsule layer. A transfer sheet obtained by locally printing a microcapsule ink containing another electron-donating color former that forms an image having a color tone different from that of the donor color former; and a microcapsule included in the microcapsule layer. Receptor provided with a layer containing an electron-accepting color developer that reacts with the electron-donating color former encapsulated in the microcapsules in the ink and develops both the electron-donating color formers In a multicolor pressure-sensitive copying paper combined with a sheet, the electron-donating color former contained in the microcapsule contained in the ink is It is a pressure-sensitive copying paper.

Wherein R ₁ , R ₂ and R ₆ are alkyl groups or cycloalkyl groups having 2 to 12 carbon atoms, and R ₃ , R ₄ and R ₅ are alkyl groups or cycloalkyl groups having 1 to 12 carbon atoms. Is shown.)

  Comparing the green-blue multicolor pressure-sensitive copying paper according to the embodiment of the present invention with the black-blue multicolor pressure-sensitive copying paper disclosed in Patent Document 1, the difference in color tone by visual observation is the same. The photocopy paper was extremely large. The difference between the green color tone and the blue color tone showing the light resistance after exposure to sunlight for 1 day is significantly better than the difference between the black color tone and the blue color tone.

Examples of the electron-donating color former encapsulated in the microcapsules in the microcapsule layer provided on the entire surface of the support are shown below. Tables 1 and 2 specify R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ in Chemical Formula ₁ .

  Among them, all of the electron donating color formers have a green color tone with the electron accepting developer. Usually, an electron-donating color former having a green color tone with an electron-accepting developer is extremely inferior in light resistance, and even when used in combination with an ultraviolet absorber, many of them are inferior in light resistance. The compounds in Table 1 are also included in the electron-donating color former of the general formula 1, but the compound of the general formula 1 has a relatively high light resistance, and when used in combination with an ultraviolet absorber, the light resistance is further improved. . H2114 manufactured by Yamada Chemical Co., Ltd. having a melting point of 182.3 to 183.4 ° C. corresponds to the electron donating color former of No. 21 in Table 1.

  The color former encapsulated in the microcapsules in the ink is a blue color former, and indolylphthalide and indolylazaphthalide are preferred from the viewpoint of dissolution stability in a solvent.

  When encapsulating the electron-donating color former, the electron-donating color former is dissolved in a hydrophobic medium and used as a core substance. As the hydrophobic medium, vegetable oils such as cottonseed oil, kerosene, paraffin, Mineral oils such as naphthenic oil and chlorinated paraffin, aromatic hydrocarbons such as alkylated biphenyl, alkylated terphenyl, alkylated naphthalene, diarylethane, triarylmethane and diphenylalkane, oleyl alcohol, tridecyl alcohol, Benzyl alcohol, alcohols such as 1-phenylethyl alcohol and glycerin, organic acids such as oleic acid, dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, dioctyl phthalate, diethyl adipate, pyropyr adipate, di-adipate n-butyl and Esters such as dioctyl dipinate, organic phosphate compounds such as tricresyl phosphate, tributyl phosphite, tributyl phosphite and tributyl phosphite oxide, ethers such as phenyl cellosolve, benzyl carbitol, polypropylene glycol and propylene glycol monophenyl ether Amides such as N, N-dimethyllauramide, N, N-dimethyl stearamide and N, N-dihexyloctylamide, ketones such as diisobutyl ketone and methylhexyl ketone, alkyl carbonates such as ethylene carbonate and propylene carbonate And the like and mixtures thereof.

As an electron-accepting developer, acid clay, activated clay, attapulgite, inorganic solid acids such as zeolite and bentonite, phenolic resins such as novolac-type phenolic resins and polyvalent metal salts thereof, polyvalent metal salts of aromatic carboxylic acids, and Examples thereof include organic developers such as salicylic acid derivatives and polyvalent metal salts such as zinc salts thereof, and zinc salts of 2,2′-bisphenolsulfone compounds.
These can also be used as a mixture.

  As salicylic acid derivatives, 3,5-di (α-methylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5- (α, α'-dimethylbenzyl) salicylic acid, 3,5-di-tert-butylsalicylic acid, Examples include 3,5-di-tert-octylsalicylic acid, 3,5-di (α, α'-dimethylbenzyl) salicylic acid, and styrenated salicylic acid.

  These microcapsules are produced by a coacervation method, an interfacial polymerization method, an in situ polymerization method, or the like. It is preferable to employ an interfacial polymerization method, an in situ polymerization method, or the like from the viewpoint of ease of production, production cost, microcapsule resistance, and the like.

  The compounding amount of the electron-donating color former in the hydrophobic medium is usually 1 part by weight or more and 100 parts by weight or less with respect to 100 parts by weight of the hydrophobic medium.

  When microencapsulating a hydrophobic solution in which a color former is dissolved, an ultraviolet absorber, a light stabilizer, an antioxidant and the like can be dissolved in the hydrophobic solvent.

The size (volume average diameter) of the color former-encapsulating microcapsules is preferably in the range of 1 to 20 μm, particularly preferably in the range of 3 to 10 μm. The coating amount of the color former, slightly different depending on the type of color former to be selected is not particularly limited, in terms of color development performance, 5 to 1000 mg / m ^2, particularly preferably from. 20 to 200 mg / m ² Range.

  The coating liquid containing the microcapsule dispersion is usually prepared as an aqueous coating liquid. The coating liquid includes latex binders, water-soluble binders, capsule protective agents (stilts), white pigments, surfactants, antifoaming agents, thickeners, preservatives, colorants, etc. as necessary. Various known materials can be added. The microcapsule content ratio in the coating liquid is 5 to 80 parts by mass in 100 parts by mass (solid part) of the coating liquid.

  Examples of the latex binder include styrene-butadiene copolymer latex, acrylonitrile-butadiene copolymer latex, vinyl acetate latex and acrylic latex, and further alkali thickening latexes thereof.

  As water-soluble binders, gelatin, albumin, casein, starch, pregelatinized starch, oxidized starch, etherified starch, esterified starch, sodium alginate, gum arabic, carboxymethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide And natural or synthetic polymer compounds such as methylcellulose. Furthermore, these can also be mixed and used. These usage-amounts are 5-100 dry solid mass parts with respect to 100 microsolid dry solid mass part, Preferably, they are 5-50 dry solid mass parts.

  Examples of capsule protective agents (stilts) include wheat starch granules, corn starch granules, pea starch granules, various plastic pigments and pulp powder. Its size (average diameter) is 1 to 100 μm, preferably 5 to 30 μm.

  Examples of white pigments include calcium carbonate, aluminum hydroxide, zinc oxide, titanium oxide, kaolin and talc.

  The coating liquid containing the microcapsule dispersion is applied and dried using a normal coating machine (coater). Examples of these coating machines include air knife coaters, blade coaters, rod coaters, bar coaters, roll coaters, size press coaters, curtain coaters, and the like.

  Capsule ink used for printing by a printing machine is a dispersion of powder capsules obtained by filtering and drying a capsule dispersion in vehicles such as organic solvents, oils, resins, waxes, and, if necessary, pigments, Various auxiliary agents known in the ink field such as capsule protective agents, surfactants, UV absorbers, antioxidants, fluorescent dyes, photopolymerization initiators, waxes, dryers, thickeners, gelling agents are added, and steam drying is performed. It is prepared as a capsule ink such as a mold, radiation curable type, oxidation polymerization type, hot melt type, etc., for example, on the above-mentioned capsule coating surface by a printing machine such as letterpress printing, intaglio (gravure) printing, planographic (offset) printing, screen printing, Applied.

Regarding printing of capsule ink, if several types of capsule ink containing chromogenic substances that have different color tones when used in color development are used properly, pressure sensitivity that develops in two or more colors along with it. It can be configured on a copy sheet. Furthermore, as a sheet | seat which prints said capsule ink, it prints on the capsule application surface of an upper sheet, and / or the capsule application surface of a middle sheet. There are no particular restrictions on the coating weight of the capsule ink, from the viewpoint of coloring properties and economy, usually 0.5 to 10 g / m ^2, more preferably about 1 to 5 g / m ^2.

  Examples of the organic solvent used for this include benzene, toluene, xylene, cyclohexane, hexane, ligroin, methyl isobutyl ketone, methyl acetate, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, Examples include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, n-hexanol, cyclohexanol, and 2-ethylhexyl alcohol.

  Specific examples of oils include vegetable oils (dry oils such as sesame oil and safflower oil, semi-dry oils such as soybean oil, non-drying oils such as castor oil), processed oils (dehydrated castor oil, polymerized oil, maleated oil) Oil, vinylated oil, urethanized oil) mineral oil (machine oil, spindle oil) and the like.

  Furthermore, as the resin, for example, natural resins such as rosin (gum rosin, wood rosin, tall oil rosin), Cerax, Copal, Dalman, Gilsonite, Zein, cured rosin, ester gum and other rosin esters, maleic acid resin, fumaric acid resin, Duplexed rosin, polymerized rosin, rosin-modified phenolic resin, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethylhydroxyethylcellulose, carboxymethylcellulose, cellulose acetate propionate, cellulose acetate butyrate, nitrocellulose and other semisynthetic resins, phenolic resin , Xylene resin, urea resin melamine resin, ketone resin, chroman-indene resin, petroleum resin, terpene resin, cyclized rubber, chlorinated rubber Alkyd resin, polyamide resin, acrylic resin, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, methyl vinyl ether-maleic anhydride Copolymers, isobutylene-maleic anhydride copolymers, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl butyral (butyral resin), polyvinyl pyrrolidone, chlorinated polypropylene styrene resin, epoxy resin, polyurethane and other synthetic resins, and polyethylene glycol Diacrylate, Puopylene glycol dimethacrylate, Pentaerythritol acrylate, Trimethylolpropane diacrylate, Pentaerythritol tetraacrylate, Hexanediol diacrylate 1, 2-butanediol acrylate, reaction product of epoxy resin and acrylic acid, reaction product of methacrylic acid, pentaerythritol and acrylic acid, condensate of maleic acid, diethylene glycol and acrylic acid, metal methacrylate, butyl methacrylate, Examples thereof include oligomers or prepolymers having an ethylenically unsaturated bond such as styrene. Furthermore, as waxes, animal waxes such as beeswax, whale wax, lanolin, plant waxes such as candelilla wax, carnauba wax, wood wax, rice wax, sugarcane wax, montan wax, ozokerite, lignite wax, etc. Petroleum wax such as mineral wax, paraffin wax, microcrystalline wax, montan wax derivative, modified wax such as paraffin wax derivative, microcrystalline wax derivative, hydrogenated wax such as caster wax, opal wax, low molecular weight polyethylene and its derivatives , Synthetic wax such as Accra wax, distearyl ketone, caproic acid amide, capric acid amide, pelargonic acid amide, capric acid amide, uraric acid amide, tridecylic acid Fatty acid amide waxes such as amide, myristic acid amide, stearic acid amide, behenic acid amide, ethylene bis stearic acid amide, caproleic acid amide, oleic acid amide, linoleic acid amide, ricinoleic acid amide, linolenic acid amide, stearic acid, behen Fatty acid waxes such as acids, alcohol waxes such as stearyl alcohol, and phosphate ester waxes such as distearyl phosphate are used alone or in combination.

  The multicolor pressure-sensitive copying paper of the present invention is used in the form of an upper sheet and a lower sheet, an upper sheet, one or a plurality of middle sheets and a lower sheet. A sheet having an anti-tampering function can be used as the lower sheet, and the anti-tampering function can be further enhanced by combining with the transfer sheet of the present invention.

  As the support, ordinary acidic papermaking, neutral papermaking, synthetic paper, film and the like are used.

  Hereinafter, although the features of the present invention will be described in detail by examples and comparative examples, the present invention is not limited to the examples. Accordingly, the substances and production conditions used in the present invention are not limited to those described in the examples. In Examples and Comparative Examples, unless otherwise specified, it is expressed in dry solid mass parts.

Preparation of blue color-based capsule coating solution and preparation of sheet 8 parts of crystal violet lactone and JF-77 made by Johoku Chemical Industry Co., Ltd. 0.5 parts 100 parts alkyl diphenylethane (trade name Hysol SAS-296, manufactured by Nippon Petrochemical Co., Ltd.) Was dissolved by heating to obtain an internal phase oil. This internal phase oil is emulsified in a solution in which 20% caustic soda solution is added to 200 parts of 3.0 aqueous solution of ethylene-maleic anhydride copolymer (trade name EMA-31, manufactured by Monsanto) to make pH 6.0. The system was then heated to 55 ° C. Separately, 15 parts of melamine was added to 45 parts of a 36% formaldehyde aqueous solution and reacted at 60 ° C. for 15 minutes to prepare a prepolymer aqueous solution. This prepolymer aqueous solution was dropped into the previously prepared emulsion, and further stirred, then heated to 80 ° C., held at that temperature for 1 hour, and then PH was lowered to 3.5 with 0.2N hydrochloric acid. After being held for 3 hours, it was allowed to cool to obtain a capsule dispersion having an average particle size of 3.6 μm.

Next, 50 parts of wheat starch powder, 30 parts of pulp powder, and 40 parts of carboxy-modified styrene-butadiene copolymer latex (solid content 50%) are added and mixed with this dispersion so that the solid content becomes 23%. To obtain a capsule coating solution. The coating amount on the base paper obtained coating solution 40 g / m ² was obtained coated blue coloring system capsule coated sheet by an air knife coater so as to be 6 g / m ^2.

Preparation of Green Coloring Capsule Ink A capsule dispersion was obtained in the same manner as the preparation of the blue coloring capsule coating solution except that 8 parts of crystal violet lactone were replaced with 10 parts of the electron donating colorant of No. 21 in Table 1. The dispersion was then filtered and washed with ethanol, and then the capsule was redispersed in a mixed medium of 330 parts of ethanol and 165 parts of n-propanol, to which 25 parts of light calcium carbonate, ethyl cellulose No. 14 (manufactured by Hercules Co., Ltd.) was added to obtain a flexo green color capsule ink.

Preparation of top sheet Printed green colored capsule ink at a speed of 80 m / min on the capsule layer surface of the previously produced blue colored capsule coated sheet with a business form printer, resulting in an ink deposit of 2.5 g / m It was obtained on a sheet containing spots printed matter 10 cm × 10 cm square is ^2.

Preparation of lower sheet 65 parts light calcium carbonate, 20 parts zinc oxide, 3.5-di (α-methylbenzyl) salicylic acid zinc salt and α-methylstyrene-styrene copolymer (mixing ratio 80) / 20) 15 parts of an aqueous polyvinyl alcohol solution (solid content) and 300 parts of water were pulverized with a ball mill for 24 hours, and a prepreg prepared by adding 20 parts of a carboxy-modified styrene-butadiene copolymer latex. The colorant coating solution was applied with an air knife coater so that the coating amount was 40 g / m ² to obtain a lower sheet.

Evaluation The upper sheet and the lower sheet obtained in this manner were overlapped, and the portion where the capsule ink was printed and the portion where the printing was not performed were printed with a typewriter to obtain a two-color developed image.

(Comparative Example 1)
The same procedure as in Example was performed, except that the electron-donating color former of No. 21 in Example was replaced with the electron-donating color former of Conventional Dye 1.

(Comparative Example 2)
The same procedure as in Example was performed, except that the electron-donating color former of No. 21 in Example was replaced with the electron-donating color former of Conventional Dye 2.

Comprehensive evaluation Randomly selected from those who are engaged in clerical work as 10 monitors, 7 males and 3 females from 20s, 30s, 40s and 50s. The multicolor pressure-sensitive copying papers obtained in 2 and 2 were compared. The items compared were the difference in color tone by visual observation, the color tone of green color showing light resistance after exposure to sunlight for one day, and the difference in color tone by visual observation.

  The evaluation of the monitors was almost the same for all. Comparing the multicolor pressure-sensitive copying paper in the example of the present invention with the multicolor pressure-sensitive copying papers of Comparative Examples 1 and 2, in the multicolor pressure-sensitive copying paper before exposure to sunlight, the examples and Comparative Example 1 are green. The developed color tone was dark and vivid, and the difference in the developed color tone was also clear. However, in Comparative Example 2, the green color tone was faint, not vivid, and could be distinguished somehow. After exposure to sunlight for 1 day, the examples were still dark and vivid in green color tone, and the differences in color tone were clear, but those in Comparative Example 1 were dark and vivid, and the difference in color tone. The color changed from a clear green color tone to a dull green or black color tone. In the case of Comparative Example 2, the color image disappeared.

Claims (1)

The microcapsule layer containing microcapsules encapsulating an electron-donating color former is provided on the entire surface of the support, and the electron-donating color that is encapsulated in the microcapsule layer when color develops on the microcapsule layer A transfer sheet obtained by locally printing a microcapsule ink containing another electron-donating color former that forms an image having a color tone different from that of the agent, and electron donation included in the microcapsule in the microcapsule layer A receptive sheet provided with a layer containing an electron-accepting color developer that reacts with an electron-donating color former encapsulated in a microcapsule in the ink and develops both of the electron-donating color formers In the multicolor pressure-sensitive copying paper, the electron-donating color former contained in the microcapsule contained in the ink is Paper.

Wherein R ₁ , R ₂ and R ₆ are alkyl groups or cycloalkyl groups having 2 to 12 carbon atoms, and R ₃ , R ₄ and R ₅ are alkyl groups or cycloalkyl groups having 1 to 12 carbon atoms. Is shown.)