JP2011032385A - Desensitizing ink and pressure-sensitive copy paper using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide desensitizing ink with which a sufficient and reliable desensitization effect is assured in a part unnecessary to be copied without causing an off-set phenomenon and a strike-through phenomenon, and to provide pressure-sensitive copy paper using the same. <P>SOLUTION: The desensitizing ink is laminatedly printed on a part unnecessary to be copied in a color developing agent layer or a color developing agent layer of pressure-sensitive copy paper. The desensitizing ink contains a radiation-curable prepolymer and/or monomer and ≥10 wt.% of non-crystalline silica having an average particle diameter of ≤3.5 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a desensitizing ink used for a pressure-sensitive copying form or the like and a pressure-sensitive copying paper using the same.

  Conventionally, a form or the like using pressure-sensitive copying paper is composed of at least an upper sheet and a lower sheet. For example, a color former is coated on the lower surface side of the upper sheet to form a color former layer, and the upper surface of the lower sheet is formed. On the side, a developer is applied to form a developer layer. Further, a desensitizing ink is coated on the developer layer in a portion where copying is not required on the lower sheet, and a desensitizing agent layer is partially formed.

  Therefore, when the entry is made on the upper surface side of the upper sheet, the color former and the developer react with each other by the writing pressure, and copying to the lower sheet is performed. At this time, even if the entry is made on the desensitizer layer on the upper sheet, color development and color development are hindered by the desensitizer, and copying to the lower sheet at that portion is avoided (for example, the following patent) Reference 1).

  As a result, it is possible to prevent leakage through the lower sheet such as secret matters to be entered only on the upper sheet.

JP 2006-15589 A JP 2000-006516 A JP 07-257072 A JP 07-216785 A JP 2002-086909 A

  Thus, today, the desensitizer layer has an important meaning from the viewpoint of preventing leakage of secret matters, and therefore, the desensitizer layer must have a sufficient and reliable desensitization effect. For this reason, in order to ensure a sufficient and reliable desensitization effect, it is generally performed to form a desensitizer layer using desensitization ink containing a large amount of desensitizer.

  However, when a desensitizer layer is formed on the lower paper using the desensitizing ink containing a large amount of desensitizer in this way, the desensitizer moves to the necessary copy portion of the lower paper. A phenomenon (hereinafter referred to as “set-off” phenomenon) occurs in which a necessary copy portion of the paper becomes defective in copying. In addition, the desensitizer moves from the desensitizer layer of the lower paper to the surface of the middle paper, and as a result, a phenomenon that the required copy portion of the middle paper becomes defective (hereinafter referred to as “strike-through” phenomenon) occurs. .

  Accordingly, a sufficient and reliable desensitization effect can be ensured in a portion that does not require copying, but there is a disadvantage in that copying failure occurs in a portion that requires copying due to a set-off phenomenon or a strike-through phenomenon. In particular, the set-off phenomenon is likely to occur when the intermediate product of the lower paper or the middle paper printed with the desensitizing ink layer is stored in a warehouse of about 40 ° C. in the summer and is being transported. When the environmental temperature is about 60 ° C. in the vehicle or ship, the strike-through phenomenon is likely to occur in the pressure-sensitive copying slip product.

  In order to solve such a defect, in Patent Document 2 (Japanese Patent Laid-Open No. 2000-006516) and Patent Document 3 (Japanese Patent Laid-Open No. 07-257072), a surface on the desensitizer layer or a surface facing the desensitizer layer. Disclosed is a technology for reducing the migration of desensitizers in the desensitizer layer by providing an overcoat layer. However, providing an overcoat layer in this way reduces productivity due to an increase in printing processes. And an increase in production costs.

  Further, in Patent Document 4 (Japanese Patent Application Laid-Open No. 07-216785), a sizing agent is placed in the middle paper and the lower paper base, and a minute gap is provided between the color former layer and the sensitizer layer. Although the technology for mitigating the transfer of the desensitizer is disclosed, the cost of the base paper increases with such technology, and the problem that the copy image is not visually recognized due to the influence of the size agent has occurred. .

  On the other hand, although there is a technique for mitigating the influence of desensitizing agent migration by appropriately controlling the coating amount of the conventional desensitizing ink by the method as shown in Patent Document 5 (Japanese Patent Application Laid-Open No. 2002-086909). In order to control the coating amount, it is necessary to always manage during production printing work, and it is necessary to adjust the printing conditions of the production machine for controlling the coating amount as appropriate. is doing.

  The present invention has been made in view of such a conventional problem, and does not require a special application amount constant management at the time of printing a desensitizer layer, and does not require a copy-off without causing a set-off phenomenon or a strike-through phenomenon. It is an object of the present invention to provide a desensitizing ink capable of ensuring a sufficient and reliable desensitizing effect on a portion and a pressure-sensitive copying paper using the same.

  In particular, even when the application amount of desensitizing ink is slightly higher than the appropriate amount, and even when it is in a 40 ° C or 60 ° C environment during storage in a warehouse in the summer or transportation by vehicle or ship, a set-off phenomenon or strike It is an object of the present invention to provide a desensitizing ink capable of ensuring a sufficient and reliable desensitizing effect in a copy unnecessary portion without causing a through phenomenon, and a pressure-sensitive copying paper using the same.

  In order to solve the above-mentioned problems, the desensitizing ink according to the present invention is a desensitizing ink which is laminated and printed on a color former layer or a developer layer of a pressure-sensitive copying paper and is curable by radiation. While containing a polymer and / or monomer, it contains 10% by weight or more of amorphous silica having an average particle size of 3.5 μm or less.

  Therefore, by containing 10% by weight or more of amorphous silica, it becomes difficult for the desensitizer to move in the desensitizer layer, and the set-off phenomenon and strike-through phenomenon can be prevented. In addition, when the average particle diameter of the amorphous silica is 3.5 μm or less, the specific surface area is larger than that of silica having an average particle diameter of more than 3.5 μm, and the color former can be adsorbed more effectively. As a result, the color former does not reach the developer layer and the desensitization effect is enhanced. Therefore, even when there is a corresponding change in the coating amount of the desensitizer layer, it is possible to prevent the set-off phenomenon and strike-through phenomenon from occurring, and to ensure the necessary desensitizing effect.

  In addition, when the desensitizer has a blending amount of 30% by weight or less, it is possible to reliably prevent the occurrence of a set-off phenomenon or strike-through phenomenon, and the desensitizing agent has a blending amount of 10% by weight or less. Then, the occurrence of the set-off phenomenon and strike-through phenomenon can be prevented more reliably. Of course, even with such a mixing ratio of the desensitizer, it is possible to ensure a necessary desensitization effect by the color former adsorbing effect of the silica.

  Here, as a desensitizing agent used in the desensitizing ink in order to inactivate a reaction that develops color by contact with a color developing agent such as a leuco dye and a color developing agent such as a phenol resin or salicylic acid, dodecyl trimethyl ammonium chloride, octadecyl chloride Quaternary ammonium salts such as dodecylammonium chloride, amines with large molecular weight such as dodecylamine: Substituted oxazolines such as 2,4,4-trimethyl-2-oxazoline: cyclic in the molecule such as xylenediamine and N-aminopropylpiperidine Reaction product of diamine or polyamine derivative having structure and alkylene oxide: polyoxyethylene alkylamine, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether polyethylene glycol polypropylene glycol, poly Carboxymethyl propylene alkylamine, a polymer having a glutamic acid -r- alkyl ester residue, spiroacetal diamine, N- (aminoalkyl) - lactams, and the like glycidyl ether adducts of amines.

  In addition, the silica has hydrophilicity on the surface, so that it is easy to adsorb a color developing agent such as a leuco dye, and it is more effective that the color developing agent reaches the developer layer. Therefore, as described above, the present inventors have invented an epoch-making desensitizing ink that can sufficiently secure a desensitizing effect even when the blending amount of the desensitizer is 30% or less, further 10% or less. .

  Examples of the silica include AEROSIL series and ACEMATT series (EVONIK), Silicia series (Fuji Silysia Chemical Co., Ltd.), MIZUKASIL series (Mizusawa Chemical Industry Co., Ltd.), and NIPSIL series (Nippon Silica Industry Co., Ltd.). The product can be selected as appropriate.

  In addition, the desensitizing ink of the present invention contains a prepolymer and / or monomer that can be cured by radiation, and does not contain an organic solvent that needs to be scattered by heat drying or the like. It is unnecessary and has no adverse environmental impact.

  Examples of the prepolymer curable by radiation include urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, and the like, and examples of the monomer include ethylene glycol, diethylene glycol, Monofunctional and polyfunctional (meth) acrylate monomers of polyhydric alcohols such as ethylene glycol, tetraethylene glycol, glycerin and trimethylolpropane and (meth) acrylic acid, and terminal epoxy (meth) acrylates of various glycidyl ethers Monofunctional and polyfunctional monomers, heterocyclic monofunctional and polyfunctional (meth) acrylate monomers having an alicyclic structure, monofunctional and polyfunctional (meth) acrylate monomers having an aromatic ring such as a phenyl structure, etc. Can.

  The prepolymer and the monomer can be used by appropriately selecting one or a plurality or combining them in order to adjust the ink to a desired viscosity, fluidity, curability and the like. Moreover, in order to adjust the flexibility of the ink coating film and the curing rate by irradiation with radiation, the prepolymer and the monomer are appropriately selected from monofunctional and polyfunctional. A combination of these may also be used.

  The desensitizing ink of the present invention can be used for various printing such as offset printing, gravure printing, flexographic printing, screen printing, inkjet printing, etc. by adjusting the blending amount of such prepolymers and monomers and designing fluidity appropriately. Can be printed in a manner.

  Furthermore, the desensitizing ink of the present invention contains a photoinitiator, so that the ink can be cured by irradiation with ultraviolet rays or LEDs to form a reduced pressure sensitive layer.

  As the photoinitiator, one or more known photopolymerization initiators can be appropriately selected and used. For example, benzoin isobutyl ether, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, benzyl, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) ) -Butan-1-one, bis (2,4,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, 1,2-octanedione, 1- (4- (phenylthio) -2, 2- (O-benzoyloxime), 1-hydroxycyclohexyl phenyl ketone, benzoin ethyl ether, benzyldimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl)- 2-hydroxy-2-methylpropa -1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, benzophenone, 4-phenylbenzophenone, isophthalphenone, 4-benzoyl-4′-methyl-diphenyl sulfide, etc. Furthermore, the curability of the desensitized ink can be promoted by adding an aliphatic amine or an aromatic amine as a photosensitizer.

  On the other hand, the desensitizing ink of the present invention may be added with an appropriate amount of vegetable oil or mineral oil to impart flexibility or flexibility, an additive for enhancing the defoaming effect or leveling effect, Various polymers can be added to increase adhesion and toughness of the ink layer, and UV absorbers, heat stabilizers and antioxidants can be added to prevent UV, thermal and oxide degradation. . Furthermore, the luster and color tone of the desensitizer layer can be adjusted by adding extender pigments or colored pigments.

  The present invention also provides a pressure-sensitive copying paper having a desensitizing layer printed with the above desensitizing ink and cured by irradiation with radiation. In such a pressure-sensitive copying paper, the pressure-sensitive copying paper is kept in a long-term storage state by relatively reducing the content of the desensitizer and containing 10% or more of the amorphous silica. Even in such a case, no set-off phenomenon or strike-through phenomenon occurs, and a necessary desensitization effect can be ensured.

  In addition, the pressure-sensitive paper has a desensitizing layer cured using ultraviolet light or an LED light source as radiation, thereby saving space and energy by using ultraviolet light or an LED light source in the manufacturing process. In addition, the production without requiring the solvent volatilization time becomes possible.

  According to the present invention, a sufficient and reliable desensitization effect can be ensured in a portion that does not require copying, without causing a set-off phenomenon or a strike-through phenomenon without performing regular application amount management adjustment in the production process. Can provide pressure-sensitive copying paper. In addition, since it does not contain an organic solvent that needs to be dispersed by heat drying or the like, adverse environmental effects can be prevented.

It is a cross-sectional schematic diagram of the pressure-sensitive copy slip concerning one embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described. As shown in FIG. 1, a pressure-sensitive copying slip 1 according to an embodiment of the present invention includes an upper sheet 2, a middle sheet 3, and a lower sheet 4. A color former layer 5 is formed on the lower surface side of the upper sheet 2 by printing or applying a color ink or a color paint containing a capsule containing a color former.

  A developer layer 6 is formed on the upper surface of the middle paper 3 by printing or applying a developer ink or developer containing a developer, and a color containing a capsule containing a color developer is formed on the lower surface. The color former layer 7 is formed by printing or applying ink or color paint. Further, a desensitizing agent layer 8 is formed on the developer layer 6 of the middle sheet 3 by printing desensitizing ink on the copy color development unnecessary portion 11.

  Further, a developer layer 9 is formed on the upper surface of the lower sheet 4 by printing or applying a developer or developer containing a developer, and on the upper side of the lower paper 4 is reduced to a portion 12 that does not require color development. The desensitizer layer 10 is formed by printing the ink-sensitive ink.

  As shown in FIG. 1, when there is only one middle sheet 3, it is usually called a three-sheet copy slip, and one having two middle sheets 3 is called a four-sheet copy slip.

Examples and Comparative Examples

  Examples of the present invention will be described below together with comparative examples. In addition, the component value in a following example and a comparative example is weight%.

By using a desensitizing ink with the composition shown in Table 1, the amount of desensitizing ink used for printing is changed to 0.30 cc, 0.35 cc, and 0.40 cc using an RI tester color developing machine, and a commercially available lower paper. And printing on the developer layer of the middle sheet, irradiating with an ultraviolet ray with an integrated light quantity of 50 mJ / cm ² to cure the desensitized ink printing layer to create a middle sheet and a lower sheet, The pressure-sensitive copying paper shown in FIG. The upper paper and the middle paper were those having a blue color former.

Note that the lower and middle sheets are printed with desensitizing ink and cured, and then folded so that the desensitized ink printing layer and non-printed areas are facing each other, as in the folding printing method specification. Then, after applying the load of 30 g / cm ^{2 in} a 40 ° C. environment and leaving it to stand for 3 days, the one in which the folding was released was used.

"Evaluation of desensitization performance"
Is the pressure-sensitive copying slip 1 shown in FIG. 1 normally filled with a ballpoint pen as written on a no-cambon copying slip, etc., and then the desensitized ink printing layer portion of the slip sheet on the slip sheet is not copyable? It was evaluated visually.

  ◎ The copy was not visible at all.

  ○ Although traces of the copy are visible, the copy lines are at an unreadable level.

  Δ: Some copy marks were visible, and it was at a level where the copy lines could be read by gaze.

× It was copied to an extent that could be easily read.
"Evaluation of set-off phenomenon"
In the pressure-sensitive copying slip shown in FIG. 1, it is usually written with a ballpoint pen so that it is written on a no-cambon copying slip, etc. The paper and the middle paper are folded and stacked, and the copy to the developer layer portion that was opposed to the desensitizer layer when left under a load of 30 g / cm ² under a 40 ° C. environment for 3 days is clear. The property was evaluated visually.

  ◎ It was a clear copy with no defects.

  ○ Although it can be fully read instantly, it was at a level where a slight decrease in copy density was felt.

  Δ: Although it was readable, the copy density was at a level that could not be said to be fully readable immediately.

  × Copy density had dropped to a level that was difficult to read even by gaze.

"Evaluation of strike-through phenomenon"
The pressure-sensitive copying slip shown in Fig. 1 is applied with a load of 30 g / cm ^{2 in} a 60 ° C environment and left for 3 days. The sharpness of the copy on the developer layer portion of the middle paper that overlapped the portion was visually evaluated.

  ◎ It was a clear copy with no defects.

  ○ Although it can be fully read instantly, it was at a level where a slight decrease in copy density was felt.

  △ Although it was readable, the copy density was at a level that was difficult to read instantly.

  × Copy density had dropped to a level that was difficult to read even by gaze.

・プレポリマー１ ２官能ウレタンアクリレート
・プレポリマー２ ２官能エポキシアクリレート
・モノマー１ ネオペンチルグリコールジアクリレート
・モノマー２ ジペンタエリスリトールペンタアクリレート
・減感剤 脂肪族アミンアルキレンオキサイド付加物
・シリカＡ 粒子径３．５μｍの表面未処理の非結晶性シリカ
・シリカＢ 粒子径２．６μｍの親水性表面である非結晶性シリカ
・シリカＣ 粒子径４．０μｍの親水性表面である非結晶性シリカ
・光開始剤 α−アミノアルキルフェノン：アシルフォスフィンオキサイド＝１：３
・白顔料 酸化チタン
・植物油 大豆油

Prepolymer 1 Bifunctional urethane acrylate Prepolymer 2 Bifunctional epoxy acrylate Monomer 1 Neopentyl glycol diacrylate Monomer 2 Dipentaerythritol pentaacrylate Desensitizer Aliphatic amine alkylene oxide adduct Silica A Particle size Amorphous silica / silica B having an untreated surface of 5 μm Amorphous silica / silica C having a hydrophilic surface with a particle diameter of 2.6 μm Amorphous silica / photoinitiator having a hydrophilic surface with a diameter of 4.0 μm α-aminoalkylphenone: acylphosphine oxide = 1: 3
・ White pigment Titanium oxide ・ Vegetable oil Soybean oil

  As the results of Examples 1 to 6 show, the desensitizing ink containing 10% by weight or more of amorphous silica having a particle diameter of 3.5 μm or less has a large amount of desensitizing agent when the coating amount varies. Regardless of the amount, it satisfies both a sufficient desensitizing effect, a sufficient set-off phenomenon resistance, and a sufficient strike-through phenomenon resistance.

  On the other hand, as shown in Comparative Examples 1 to 4, in the desensitized ink that does not contain 10% by weight or more of amorphous silica having a particle size of 3.5 μm or less, there is a large amount of desensitizing agent when there is a variation in coating amount. Therefore, sufficient desensitization effect, sufficient set-off phenomenon resistance, and sufficient strike-through phenomenon resistance cannot be satisfied at the same time.

DESCRIPTION OF SYMBOLS 1 Pressure-sensitive copy slip 2 Upper paper 3 Medium paper 4 Lower paper 5 Color developing agent layer 6 Developer layer 7 Color developing agent layer 8 Desensitizing agent layer 9 Developer layer 10 Desensitizing agent agent layer 11 Copying coloring unnecessary part 12 Copy color development Unnecessary part

Claims (7)

A desensitizing ink that is laminated and printed on a color-developer layer or a developer layer of pressure-sensitive copying paper that does not require copying,
A desensitizing ink comprising a prepolymer and / or a monomer curable by radiation, and containing 10% by weight or more of amorphous silica having an average particle size of 3.5 μm or less.   The desensitizing ink according to claim 1, wherein the desensitizing agent is a blending amount of 30% by weight or less.   The desensitizing ink according to claim 1, wherein the desensitizing agent is a blending amount of 10% by weight or less.   The desensitizing ink according to claim 1, 2 or 3, wherein the silica has a hydrophilic surface.   Furthermore, it contains a photoinitiator, The desensitizing ink in any one of Claim 1 to 4 characterized by the above-mentioned.   6. A pressure-sensitive copying paper comprising a desensitizing layer printed with the desensitizing ink according to claim 1 and cured by irradiation with radiation.   7. The pressure-sensitive copying paper according to claim 6, wherein the radiation has a desensitizing layer cured using ultraviolet light or an LED light source.

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