JP2007106044A - Pressure sensitive recording paper and pressure sensitive duplicating paper using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure sensitive recording paper, in which no bleeding of ink develops, which is excellent in color developing properties and in printability due to the high surface strength of its developing layer and which is especially suitably used for form printing employing an ink jet recording system therein, and a pressure sensitive duplicating paper using thereof. <P>SOLUTION: In the pressure sensitive recording paper consisting of a base material and a developing layer provided on one side of the base material, the developing layer is made of a developer coating including a binder, a developer and a pigment under the condition that the binder includes a modified starch and the average particle diameter of the pigment is set to be 1-10 μm. Also the pressure sensitive duplicating paper using the pressure sensitive recording paper is dealt. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive recording paper and a pressure-sensitive copying paper using the same. More specifically, the present invention relates to a pressure-sensitive recording paper that can be suitably used for form printing that employs an inkjet recording method, and a pressure-sensitive copying paper using the pressure-sensitive recording paper.

  As a paper that can be copied without using carbon paper, a pressure-sensitive recording paper in which a color developing layer is formed on one surface of a base material is known (for example, Patent Document 1). A pressure-sensitive recording paper is generally used as a pressure-sensitive copying paper combined with a paper having a coloring layer rather than being used alone, and is widely used for various slips. FIG. 3 is a schematic cross-sectional view showing an example of the configuration of pressure-sensitive copying paper using pressure-sensitive recording paper.

  In FIG. 3, the pressure-sensitive copying paper 20 includes an upper paper 21, a middle paper 22, and a lower paper 23. The upper paper 21 includes a base material 24 and a coloring layer 25 formed on one surface of the base material 24. The color developing layer 25 contains microcapsules 26, and the microcapsules 26 contain a color developing solution in which an electron donating organic compound (hereinafter referred to as “coloring agent”) or the like is dissolved. The middle sheet 22 includes a base material 24, a color development layer 25 containing microcapsules 26 formed on one surface of the base material 24, and a color development layer 27 formed on the other surface of the base material 24. It is a pressure sensitive recording paper. The color developing layer 27 is formed of a color developer composition (hereinafter referred to as “color developer”) containing an electron accepting compound as a main component, and the color developer is brought into contact with the color developer. Color. The lower paper 23 is a pressure-sensitive recording paper having a base material 24 and a color developing layer 27 formed on one surface of the base material 24.

  The upper sheet 21, the middle sheet 22 and the lower sheet 23 configured as described above are stacked in this order, and the color developing layer 25 and the color developing layer 27 are opposed to each other, so that pressure sensitive copying is performed. The paper 20 is configured. In the pressure-sensitive copying paper 20, when a writing pressure or a pressure is applied to the base material 24 of the upper paper 21, the microcapsules 26 included in the coloring layer 25 are destroyed, and the coloring solution adheres to the developing layer 27. The color develops when the color former and the developer react. Thereby, for example, the same characters as those written on the upper paper 21 are also copied to the middle paper 22 and the lower paper 23. In addition to the combination of the upper paper 21, the middle paper 22, and the lower paper 23, the pressure-sensitive copying paper 20 includes a combination of the upper paper 21 and the lower paper 23, or between the upper paper 21 and the lower paper 23. In addition, there are combinations of the necessary number of medium sheets 22 sandwiched therebetween. Hereinafter, one unit of such a combination is referred to as a “copy set”.

By the way, with the advancement of the ink jet technology, a form printing machine capable of printing variable information by an ink jet recording method has recently appeared. Form printing using the inkjet recording method employs a method of directly outputting computer data called the on-demand method. In addition to the conventional print design, variable information such as address and barcode can be printed simultaneously. Can do. Therefore, there is an advantage that small lots and various types of printing that are expensive in offset printing can be performed at a lower cost and with added value. Therefore, variable information printing by an ink jet recording method is desired for the pressure-sensitive copying paper 20 in addition to printing by a conventional printing unit.
Japanese Patent No. 3373213

  However, when variable information printing is performed on the pressure-sensitive copying paper 20 by the ink jet recording method, there is a problem that ink bleeding tends to occur. For example, barcodes, which are automatic recognition means that represent information such as alphabets and numbers in a one-dimensional black and white pattern and can be digitally input to a computer, are composed of thin lines. Is printed, a line having a predetermined width blurs and becomes thick, so that it is difficult to accurately print necessary information. In addition, when white characters are printed, the characters are crushed. These problems may occur for the following reasons.

  For example, when pressure sensitive copy paper 20 is used as a voucher, a large number of copy sets are used in a stacked manner. For ease of handling, glue or the like is applied to one side of a plurality of stacked copy sets. Apply and do so-called grouping. In grouping, the sheets that make up each copy set are integrated by infiltrating the grouping glue between the sheets, while making it difficult for the grouping glue to permeate between the copying sets, and the copy set with weak adhesive strength. Hold each other. As a result, even from among a large number of copy sets, it is possible to take out one copy set at a time without separating the sheets constituting the copy set.

  Therefore, in the pressure-sensitive copying paper 20 grouped as described above, for example, the color developing layer 27 between the upper paper 21 and the middle paper 22 and the color developing between the middle paper 22 and the lower paper 23 are used. The layer 27 is configured to facilitate penetration of the grouping glue. However, the problem here is that the adhesive paste easily penetrates into the color developing layer 27, and that other liquids also easily penetrate into the color developing layer 27. For this reason, when a pressure sensitive recording paper used as the middle paper 22 or the lower paper 23 is printed with, for example, an address, a barcode, or a simple frame line as variable information by an ink jet recording method or the like, the developed layer Since liquid easily penetrates into the ink 27, ink bleeding easily occurs.

  Therefore, in Patent Document 1, as a means for suppressing ink bleeding in the color developing layer 27, a pressure-sensitive copying paper further provided with an ink receiving layer containing a cationic resin and an inorganic pigment is proposed. However, in such a configuration, the developer contained in the color developing layer 27 aggregates due to the cationic resin contained in the ink receiving layer, resulting in problems in paint handling and coating properties, and a decrease in color developability. There is a problem of doing.

  Further, the color developing layer 27 configured to easily penetrate the grouping glue has a low surface strength, so that powder is likely to fall off during printing, thereby causing a problem that the blanket surface of the printing machine becomes dirty. Such blanket stains cause printing omission and printing stains.

  Accordingly, an object of the present invention is excellent in printability because there is no ink bleeding, excellent color developability, and the surface strength of the color developing layer is high, and it is particularly suitable for form printing employing an ink jet recording method. And a pressure-sensitive copying paper using the pressure-sensitive recording paper.

  That is, the present invention is a pressure sensitive recording paper provided with a base material and a color developing layer on one surface of the base material, wherein the color developing layer contains a binder, a color developer and a pigment. The present invention relates to a pressure-sensitive recording paper which is formed of a paint, wherein the binder contains a modified starch, and an average particle diameter of the pigment is 1 to 10 μm.

  The pressure-sensitive recording paper having such a structure is a developer capable of penetrating the grouping glue as much as necessary for adhesion of the paper by using a developer paint containing a specific component such as a binder containing modified starch. A color layer can be formed. Further, by setting the average particle diameter of the pigment within a specific range, a color developing layer having high surface strength and good color development can be obtained.

  As the modified starch, at least one selected from oxidized starch, phosphate starch, hydroxyethyl etherified starch and urea phosphate starch can be preferably used.

  Further, the color development can be further improved by including calcium carbonate having a specific potato chestnut shape as the pigment and including a weak cationic polyamide resin in the developer coating. This makes it possible to obtain pressure-sensitive recording paper that does not bleed ink even when variable information is printed using the inkjet recording method, has excellent printability and color development properties, and eliminates processing fog and dust fall. Therefore, dirt such as so-called paper dust and printing omission due to the dirt on the surface of the printing press blanket can be reduced.

  The present invention further relates to a pressure-sensitive copying paper using the pressure-sensitive recording paper. By using the pressure-sensitive recording paper of the present invention as the middle or lower paper of pressure-sensitive copying paper, it is possible to penetrate the grouping glue as much as necessary for the adhesion of the paper, and when printing with the ink jet recording method There can be obtained pressure-sensitive copying paper having no ink bleeding, excellent color developability, and having reduced stains such as paper dust and printing omission based on this, and excellent printability.

  The pressure-sensitive recording paper of the present invention has no ink bleeding, excellent color developability, and high surface strength of the color developing layer, so that it is excellent in printability, and is particularly suitable for form printing employing an ink jet recording method. can do. In addition, the pressure-sensitive copying paper of the present invention using such pressure-sensitive recording paper may cause ink bleeding even in the printing process by the ink jet recording method while penetrating the grouping glue as necessary for the adhesion of the paper. And excellent printability.

  Hereinafter, a pressure-sensitive recording paper according to an embodiment of the present invention and a pressure-sensitive copying paper using the same will be described. FIG. 1 is a schematic cross-sectional view showing the configuration of a pressure-sensitive recording paper according to this embodiment. As shown in FIG. 1, the pressure-sensitive recording paper 1 includes a base material 2 and a developer layer 3 formed on one surface of the base material 2. FIG. 2 is a schematic cross-sectional view showing an example of the configuration of the pressure-sensitive copying paper according to this embodiment, and shows the configuration of the pressure-sensitive copying paper 15 created in the examples described later. The basic configuration of the pressure-sensitive copying paper according to this embodiment is almost the same as the configuration of the pressure-sensitive copying paper shown in FIG. The same reference numerals are given, and description thereof is omitted below.

  The developer layer 3 provided on one surface of the substrate 2 is formed by a developer paint containing a binder, a developer, and a pigment. Here, the binder which is a feature of the present embodiment includes modified starch. Thus, by including the modified starch as a binder, not only can the color developability be improved, but, as will be described later, when the pressure-sensitive recording paper is used as the pressure-sensitive copying paper, It is possible to infiltrate as much of the grouping glue as is necessary for the adhesion.

  As the modified starch contained in the binder, for example, at least one selected from oxidized starch, phosphate starch, hydroxyethyl etherified starch and urea phosphate starch can be preferably used. These modified starches may be used alone or in combination of two or more. Among these, oxidized starch can be particularly preferably used from the viewpoint that color developability is further improved.

  In addition to the modified starch, the binder preferably contains, for example, styrene butadiene rubber or a dispersant.

  The styrene butadiene rubber used in the present embodiment is not particularly limited, but the particle size tends to affect the color developability and surface strength of the color developing layer 3. When such styrene butadiene rubber is used, a dispersant is usually used at the same time in order to uniformly disperse and stabilize. However, when the particle size of the styrene butadiene rubber is too small, the amount of the dispersant in the binder Therefore, the color developability (color density) tends to decrease. Conversely, if the particle size of the styrene butadiene rubber is too large, it will be difficult to uniformly disperse the styrene butadiene rubber in the developer coating, and at the same time the surface strength of the developer layer 3 will be reduced. Also, the sharpness of the image at the time of ink jet printing tends to be lowered. This decrease in the surface strength of the color developing layer 3 may cause powder falling, processing fogging, and the like, and may cause surface contamination of the printing press blanket. Therefore, the average particle diameter of the styrene butadiene rubber is preferably 130 nm or more, more preferably 160 nm or more, particularly 170 nm or more, and 240 nm or less, more preferably 210 nm or less, and particularly preferably 200 nm or less.

  When the styrene butadiene rubber as described above is used, the blend ratio of the styrene butadiene rubber and the modified starch is a dry mass ratio, (styrene butadiene rubber) :( modified starch) = 1: 1 to 1: 3, and further 1 : It is preferable to set it as the range of 1.4-1: 2.2. When the blending ratio of the modified starch to the styrene-butadiene rubber is less than 1, ink bleeding tends to occur when variable information printing is performed by the ink jet recording method. On the other hand, when the blending ratio of the modified starch to the styrene butadiene rubber is more than 3, the surface strength of the color developing layer 3 is lowered and the stability of the color developer coating is deteriorated. There is also a tendency for workability to decrease.

  Further, when a dispersant is added to the binder, the type and amount thereof are not particularly limited as long as the styrene butadiene rubber is uniformly dispersed as described above, and may be appropriately selected according to the average particle diameter and the amount of use of the styrene butadiene rubber. It is preferable to select and adjust.

  The amount of the binder contained in the color developer coating is 60 to 80% by mass in consideration of the effect of improving the characteristics of the color developing layer 3 such as the suitability for application to the substrate 2, the color developability, and the surface strength. It is preferable that it is 65-75 mass%.

  The developer contained in the developer paint is not particularly limited, and is generally used in the field of carbonless pressure-sensitive copying paper and pressure-sensitive recording paper, for example, a novolac type phenol resin and a polyvalent metal salt thereof, Salicylic acid, salicylic acid derivatives, polyvalent metal salts thereof and the like can be preferably used.

  Specifically, examples of the novolak type phenol resin and the polyvalent metal salt thereof include phenol formaldehyde resin, phenol acetaldehyde resin, phenol acetylene resin, and polyvalent metal salts thereof. Examples of salicylic acid, salicylic acid derivatives and polyvalent metal salts thereof include salicylic acid, 3,5-dinitrosalicylic acid, 5-tert-butylsalicylic acid, 3-phenylsalicylic acid, 3-methyl-5-tert-butylsalicylic acid, 3,5 -Di-tert-butylsalicylic acid, 3,5-di-tert-amylsalicylic acid, 3-cyclohexylsalicylic acid, 5-cyclohexylsalicylic acid, 3-methyl-5-isoamylsalicylic acid, 5-isoamylsalicylic acid, 3,5-di-sec -Butylsalicylic acid, 5-nonylsalicylic acid, 5,5-methylenedisalicylic acid, 3,5-di (α, α-dimethylbenzyl) salicylic acid, 3,5-di (α-methylbenzyl) salicylic acid, salicylic acid novolak resin, salicylic acid And alkoxyxylene, trialkylben Emissions, a copolymer of compounds such as styrene derivatives, etc. These polyvalent metal salts. These developers can be used alone or in combination of two or more. Among these, a developer composed of an organic solid acid compound can be suitably used because it has a high color density and good water resistance, light resistance, and stability over time. Multivalent metal salts can be preferably used.

  The amount of the developer contained in the developer paint is 3 to 15% by mass, further 5 in consideration of the effect of improving the characteristics of the developer layer 3 such as the color density, water resistance, light resistance and stability over time. It is preferable that it is -10 mass%.

  The pigment contained in the developer coating is not particularly limited, and conventionally used, for example, acid carbonate, activated clay, calcium carbonate such as heavy calcium carbonate, light calcium carbonate, calcium sulfate, kaolin, calcined kaolin Normal inorganic white pigments such as talc, aluminum hydroxide, aluminum silicate, magnesium oxide, magnesium carbonate, magnesium sulfate, zinc oxide, finely divided silicic acid, titanium oxide, calcium silicate, urea-formaldehyde resin, etc. It can be suitably used alone or in combination of two or more. Among these, heavy calcium carbonate and light calcium carbonate can be particularly preferably used, and these calcium carbonates are used in combination with a developer composed of an organic solid acid compound among the developers. By doing so, the color developability of the color developing layer 3 can be further improved.

  There is no particular limitation on the particle diameter of the pigment, but if it is too small, the surface strength of the color developing layer 3 may be reduced, which may cause blanket stains and paper dust during printing. The diameter is preferably 1 μm or more, more preferably 2 μm or more. If the particle diameter is too large, ink bleeding tends to occur, and the average particle diameter is preferably 10 μm or less, more preferably 6 μm or less.

  In particular, for the calcium carbonate, the shape generally includes a chestnut shape, a spindle shape, a cubic shape, a needle shape, etc., but in the present embodiment, among them, when a chestnut-shaped calcium carbonate is blended, pressure sensitivity When the recording paper 1 is used as the middle paper or the lower paper of the pressure-sensitive copying paper 15, the microcapsules 26 contained in the coloring layer 25 can be effectively destroyed to further enhance the coloring property.

  In the present embodiment, the chestnut-shaped calcium carbonate refers to a shape in which several spindle-shaped calcium carbonates are aggregated. In particular, the average particle diameter of the chestnut-shaped calcium carbonate is an average value of the particle diameters obtained by measuring the outermost diameter of the calcium carbonate using Microtrac (manufactured by Nikkiso Co., Ltd.).

  The amount of the pigment contained in the developer coating is preferably 10 to 90% by mass, and more preferably 15 to 85% by mass in consideration of the effect of improving the characteristics of the color developing layer 3 such as surface strength and color developability. .

  Furthermore, in the present embodiment, it is preferable that the developer paint contains a weak cationic polyamide resin in order to further improve the fixing property of the ink when printing is performed by the ink jet recording method.

  In general, the color developing layer 3 is anionic, and since the ink jet dye used in the ink jet recording method is also anionic, the color developing layer 3 and the ink jet dye do not bind at the time of printing, and the fixability of the dye. It is known that it is low and easily causes ink bleeding. In order to solve such a problem, an attempt has been made to blend a cationic resin as a dye fixing agent. However, when such a cationic resin is blended, agglomeration occurs in the developer paint and the base material is formed. The coatability to 2 may deteriorate. Therefore, in the present embodiment, it is preferable to add a weak cationic polyamide resin to the developer paint that does not cause aggregation in the developer paint while improving the fixing property of the inkjet dye. As a result, it is possible to obtain a developer paint that is more excellent in suitability for application to the substrate 2 and to further reduce ink bleeding in the developer layer 3.

  Examples of the weak cationic polyamide resin include polyamide / epoxy resin and polyamide / urea resin, and these can be used alone or in combination of two or more. In the present embodiment, the weak cationic property means a property that hardly exhibits a cationic property and does not aggregate when added to a paint having an anionic property of pH 9 or higher.

  If the amount of the weak cationic polyamide resin contained in the developer coating is too small, it tends to be difficult to sufficiently obtain the fixing effect of the ink jet dye. For example, since the amount of the developer contained in the formed developer layer 3 is reduced, the color developability is lowered, and the developer paint tends to aggregate. It is preferably 20% by mass.

  In addition to the weak cationic polyamide resin, the developer paint may further contain a cationic resin as appropriate. Examples of the cationic resin include dimethyldianylammonium chloride polymer, allylamine salt polymer, diallylamine hydrochloride polymer, diallylamine hydrochloride-acrylamide copolymer, dimethyldianylammonium chloride-acrylamide copolymer, dimethylamine. -Epichlorohydrin polycondensate, dimethylamine-ammonia-epichlorohydrin polycondensate, methacryloyloxyethyltrimethylammonium chloride polymer, dicyandiamide-diethylenetriamine polycondensate, dicyandiamide-formalin polycondensate, and the like. More than one species can be used in combination.

  In addition, as long as the characteristics of the developer paint are not impaired, for example, a pigment dispersant, a pH adjuster, a water retention agent, a thickener, an antifoaming agent, a preservative, a colorant, a water resistant agent, a wetting agent, a fluorescent agent, and the like. Various conventionally known additives such as dyes, ultraviolet absorbers, and cationic polymer electrolytes may be appropriately blended.

  The base material 2 constituting the pressure-sensitive recording paper 1 is not particularly limited. For example, foam paper, high quality paper, Yankee paper, kraft paper, paperboard, liner, newspaper, glassine paper, parchment paper using chemical pulp or mechanical pulp. A film material or a sheet material such as a resin film made of polyethylene terephthalate, a composite film of paper and a resin film, or the like can be used. In addition, recycled paper and the like recycled by separating the paper once printed can be used. When such recycled paper is used, the cost can be reduced.

  As described above, according to the present embodiment, even if the modified starch is blended as the binder contained in the color developing layer 3, the ink in the color developing layer 3 can be applied to variable information printing by the ink jet recording method. Bleeding can be eliminated. Further, by using a pigment having a predetermined particle diameter, it is possible to obtain a pressure-sensitive recording paper 1 having excellent color developability.

  As described in the background art, the pressure-sensitive recording paper 1 according to the present embodiment is a pressure-sensitive copying paper 15 composed of a copy set in which an upper sheet and a lower sheet are combined, for example, as a slip or the like. It can be used as a pressure-sensitive copying paper 20 composed of a copying set in which paper, middle paper, and lower paper are combined. In the case of pressure-sensitive copying paper composed of a copying set as described above, it is possible to perform grouping satisfactorily only by infiltrating the minimum grouping glue required for adhesion of the sheet, and ink jet recording. At the time of printing by the method, ink permeation in the color developing layer 3 can be reduced to eliminate ink bleeding, and there is a remarkable effect that the color developability is excellent. As a result, the pressure-sensitive copying paper according to the present embodiment exhibits excellent printability even when applied to variable information printing by the ink jet recording method.

  In the present embodiment, the ink bleeding generated in the color developing layer 3 is an ink jet recording method in which a bar code, a frame line, or the like is applied to the color developing layer 3 when the pressure sensitive recording paper 1 is used as a middle paper or a lower paper. When the pressure-sensitive recording paper 1 is used as the pressure-sensitive copying paper 15 (pressure-sensitive copying paper 20), a pressure is applied to the base material 24 of the upper paper 21, and copying is performed on the developing layer 3. Including both cases.

  Hereinafter, a method for producing the pressure-sensitive recording paper 1 according to the present embodiment will be described with an example. First, a binder and a pigment, and if necessary, a weak cationic polyamide resin and other various additives are mixed at a predetermined ratio. Next, a developer paint is prepared by dispersing the developer in the obtained solution. The developer coating is applied to at least one surface of the substrate 2 to form the developer layer 3. As described above, the developer paint used in the present embodiment is excellent in coating suitability without aggregation of the developer, and thus can be satisfactorily applied to the substrate 2.

There is no particular limitation on the coating method of the developer paint, for example, using a gravure coater, air dryer, air knife coater, roll coater, brush coater, die coater, knife coater, blade coater, size press coater, curtain coater, etc. More known methods and coating machines can be used. Although there is no particular limitation to the coating amount of the developer coating to the substrate 2, in view of the coloring property and cost, 2 to 20 g / m ² about, it furthermore is about 3 to 15 g / m ² preferable. Moreover, it is preferable that the thickness of the color development layer 3 formed with such a coating amount is about 0.01-1000 nm.

  Then, if necessary, a pressure-sensitive recording paper 1 is obtained by applying a solution containing microcapsules containing a color developing solution to the other surface of the substrate to form a color developing layer. There are no particular limitations on the formation method and configuration of the color-developing layer. For example, it may be the same as that conventionally known. For example, as shown in FIG. 2, the obtained pressure-sensitive recording paper 1 is a paper having a coloring layer 25 formed by applying a solution containing microcapsules 26 on one surface of a base material 24. 21 and used as pressure-sensitive copying paper 15 by laminating the color developing layer 25 of the upper paper 21 and the color developing layer 3 provided on one side of the substrate 2 so as to face each other. it can.

  The pressure-sensitive recording paper produced as described above is less likely to cause ink bleeding and develop color even when an address, a barcode, or the like is printed on the developer layer using an ink jet recording printer. It is excellent and the surface strength of the color developing layer is high, so it is excellent in printability, can eliminate picking without picking, and can eliminate blanket stains. In addition, pressure-sensitive copying paper produced using such pressure-sensitive recording paper may cause bleeding even in printing processing using an ink-jet recording method while penetrating the grouping glue as much as necessary for adhesion of the paper. And excellent printability.

  Next, the pressure-sensitive recording paper of the present invention and the pressure-sensitive copying paper using the same will be specifically described based on examples, but the present invention is not limited to these examples. In addition, the measurement of the various physical-property values in an Example and a comparative example was implemented with the following method.

(1) Coating suitability Using a coating machine (Ishikawajima-Harima Heavy Industries Co., Ltd., model number: test coating machine), the developer coating material is a base material (Daio Paper Co., Ltd., trade name: Taiou). The coating was applied at a coating amount of 4.0 g / m ² and evaluated according to the following evaluation criteria.
(Evaluation criteria)
(Double-circle): It was able to apply uniformly.
○: The viscosity was adjusted by dilution and coating was possible.
X: The viscosity was high, and even if the viscosity was adjusted by dilution, it could not be applied.

(2) Ink bleeding Solid printing of 2 cm × 2 cm in black on the color developing layer 3 of the pressure-sensitive recording paper 1 using a continuous ink jet printer (Cytex Digital Printing, model number: Scitex 6240) (Filling printing) was performed. The ink bleeding at this time was visually observed and evaluated according to the following evaluation criteria.
(Evaluation criteria)
(Double-circle): There was no ink bleeding and it was in a very good state.
◯: There was no ink bleeding and it was in a good state.
X: Ink bleeding occurred until a problem occurred in actual use.

(3) Blanket dirt Using a form rotary printing press (manufactured by Taiyo Machinery Co., Ltd., model number: TOF-200), a border line of slips is printed on the color developing layer 3 of the pressure-sensitive recording paper 1, and paper dust Confirmed the printing time deposited on the blanket, and evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: No stain was observed on the blanket even after printing 50000 m.
A: When printing 50000 m, a slight stain was observed on the blanket.
X: Dirt was recognized on the blanket before printing 30000 m.

(4) Color developability Printing was performed on the pressure-sensitive copying paper 15 using a dot printer (manufactured by NEC Corporation, model number: PC-PR201 / 65). Then, the print density copied on the lower paper 10 (pressure-sensitive recording paper 1) is measured using a Macbeth densitometer (model number: RD914, Latten # 106 filter), and based on the color density value, the following evaluation criteria are used. evaluated.
(Evaluation criteria)
A: Color density value was 0.50 or more.
A: The color density value was 0.45 or more and less than 0.50.
X: The color density value was less than 0.45.

Example 1
In producing the pressure-sensitive recording paper 1 having the same structure as that shown in FIG. 1, first, a developer coating was prepared. As a binder, 35 parts by mass of styrene butadiene rubber (manufactured by Japan A & L, product number: P-9634, average particle size: 170 nm) and 35 parts by mass of modified starch (manufactured by Oji Cornstarch Co., Ltd., product number: Oji Ace B) Was used. The dry mass ratio between them is (styrene butadiene rubber) :( modified starch) = 1: 1. As pigments, chestnut-shaped calcium carbonate (Okutama Kogyo Co., Ltd., product number: TP121, average particle size: 4 μm) 10 parts by mass, spindle-shaped calcium carbonate (Maruo Calcium Co., Ltd., product number: calcite spindle Mold, average particle diameter: 4 μm) and 10 parts by mass.

  The binder and pigment were mixed with 4 parts by mass of a weak cationic polyamide resin (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumire Resin SR-1005) to prepare a solution. Next, 6 parts by mass of zinc 3,5-di (α-methylbenzyl) salicylate as a developer was mixed with this solution, and uniformly dispersed with a sand grinder to obtain a developer paint.

One side of the base material 2 (manufactured by Daio Paper Co., Ltd., trade name: Taio) using the obtained developer paint using a coating machine (manufactured by Ishikawajima-Harima Heavy Industries Co., Ltd., model number: test coating machine) The coating was applied at a coating amount of 4.0 g / m ² , and coating suitability was evaluated based on the evaluation method. The evaluation results are shown in Table 1.

  The coated developer was dried to form a developer layer 3 having a thickness of 0.4 nm on one side of the substrate 2 to obtain an A4 size pressure-sensitive recording paper 1.

Next, as shown in FIG. 2, the obtained pressure-sensitive recording paper 1 is used as the lower paper 10, and a commercially available carbonless paper (basis weight: 40 g / m ² ) is used as the upper paper 21. The color layer 3 and the color developing layer 25 including the microcapsules 26 of the upper paper 21 were laminated so as to face each other, whereby a pressure-sensitive copying paper 15 was produced.

  The obtained pressure-sensitive recording paper 1 and pressure-sensitive copying paper 15 were used to evaluate ink bleeding, blanket stains, and color developability based on the evaluation method. The evaluation results are shown in Table 1.

(Examples 2 to 4)
A pressure-sensitive recording paper 1 and a pressure-sensitive copying paper 15 were prepared in the same manner as in Example 1 except that the blending ratio of styrene butadiene rubber and modified starch was changed as shown in Table 1, and various physical properties were evaluated. The obtained evaluation results are shown in Table 1.

(Examples 5 to 9)
A pressure-sensitive recording paper 1 and a pressure-sensitive copying paper 15 were prepared in the same manner as in Example 2 except that the average particle diameter of styrene-butadiene rubber was changed as shown in Table 1, and various physical properties were evaluated. The obtained evaluation results are shown in Table 1.

(Examples 10 to 13)
A pressure-sensitive recording paper 1 and a pressure-sensitive copying paper 15 were prepared in the same manner as in Example 3 except that the average particle size of the potato chestnut-shaped calcium carbonate was changed as shown in Table 1, and various physical properties were evaluated. The obtained evaluation results are shown in Table 1.

(Examples 14 to 16)
A pressure-sensitive recording paper 1 and a pressure-sensitive copying paper 15 were prepared in the same manner as in Example 7 except that the type of modified starch was changed as shown in Table 1, and various physical properties were evaluated. The obtained evaluation results are shown in Table 1.

  In each of Examples 1 to 16, since a developer paint containing a binder containing a modified starch, a developer, and a pigment having an average particle diameter of 1 to 10 μm is used, the application of the developer paint is performed. The pressure-sensitive recording paper 1 and the pressure-sensitive copying paper 15 using the same were obtained, which had good aptitude and had almost no ink bleeding or blanket stain even after printing or printing.

  Especially in Examples 1-4, 6-8, 11, 12, and 14-16, the average particle diameter of styrene butadiene rubber, which is a component of the binder, is within the more preferable range according to this embodiment. Since the average particle diameter of the chestnut-shaped calcium carbonate, which is a component of the pigment, is within the preferred range according to this embodiment, the surface strength of the color developing layer 3 is high, and blanket stains are observed after printing on a foam rotary printing press. Did not occur.

  In Examples 1 to 4, 6 to 8, and 10 to 13, the average particle diameter of the styrene butadiene rubber is a more preferable range according to this embodiment, and oxidized starch is used as a modified starch that is a component of the binder. Since it was used, a product excellent in color development was obtained.

  In Examples 2, 3, 5-9, 11, 12, and 14-16, the blending ratio of the styrene butadiene rubber and the modified starch is within the more preferable range according to the present embodiment. Since the average particle diameter of calcium carbonate is within a more preferable range according to the present embodiment, a product excellent in ink bleeding and coating suitability was obtained.

(Comparative Example 1)
A pressure-sensitive recording paper 1 and a pressure-sensitive copying paper 15 were prepared in the same manner as in Example 1 except that the modified starch was not used, and various physical properties were evaluated. The obtained evaluation results are shown in Table 2.

(Comparative Example 2)
A pressure-sensitive recording paper 1 and a pressure-sensitive copying paper 15 were prepared in the same manner as in Example 3 except that the average particle size of the potato chestnut-shaped calcium carbonate was made smaller than the range of the present invention, and various physical properties were evaluated. The obtained evaluation results are shown in Table 2.

(Comparative Example 3)
A pressure-sensitive recording paper 1 and a pressure-sensitive copying paper 15 were produced in the same manner as in Example 3 except that the average particle size of the potato chestnut-shaped calcium carbonate was larger than the range of the present invention, and various physical properties were evaluated. The obtained evaluation results are shown in Table 2.

(Comparative Example 4)
The pressure sensitive was the same as in Example 2 except that the average particle size of the styrene butadiene rubber was changed as shown in Table 2 without using modified starch, and a plate-shaped kaolin was used instead of the chestnut-shaped calcium carbonate. Recording paper 1 and pressure-sensitive copying paper 15 were prepared and various physical properties were evaluated. The obtained evaluation results are shown in Table 2.

(Comparative Example 5)
Except for using modified starch and using cubic calcium carbonate (manufactured by Maruo Calcium Co., Ltd., product number: calcite cube, average particle size: 4 μm) instead of chestnut-shaped calcium carbonate, the same as in Example 7 Thus, pressure-sensitive recording paper 1 and pressure-sensitive copying paper 15 were prepared, and various physical properties were evaluated. The obtained evaluation results are shown in Table 2.

(Comparative Example 6)
Without using modified starch, needle-shaped calcium carbonate (manufactured by Maruo Calcium Co., Ltd., product number: aragonite needle shape, average particle size: 4 μm) is used instead of weak chestnut-shaped calcium carbonate, instead of weakly cationic polyamide resin. A pressure-sensitive recording paper 1 and a pressure-sensitive copying paper 15 were prepared in the same manner as in Example 7 except that an anionic polyamide resin was used, and various physical properties were evaluated. The obtained evaluation results are shown in Table 2.

(Comparative Example 7)
A pressure-sensitive recording paper 1 and a pressure-sensitive copying paper 15 were prepared in the same manner as in Example 2 except that the modified starch was not used and a cationic polyamide resin was used instead of the weak cationic polyamide resin, and various physical properties were evaluated. did. The obtained evaluation results are shown in Table 2.

  In Comparative Examples 1 and 4 to 7, since modified starch, which is one component of the binder, is not used, ink bleeding is large and color developability is poor.

  In Comparative Example 2, the average particle size of the chestnut-shaped calcium carbonate, which is a component of the pigment, is smaller than the range of the present invention, so that the coating suitability is inferior and the surface strength of the color developing layer 3 is reduced during printing. Blanket stains occurred. In Comparative Example 3, on the contrary, the average particle size of the chestnut-shaped calcium carbonate was larger than the range of the present invention, so that the coating suitability was inferior and ink bleeding occurred.

  The pressure-sensitive recording paper of the present invention can be suitably used as a middle sheet or a lower sheet of pressure-sensitive copying paper. In addition, the pressure-sensitive copying paper of the present invention using such pressure-sensitive recording paper can be suitably used for form printing employing an ink jet recording system.

FIG. 2 is a schematic cross-sectional view illustrating a configuration of a pressure-sensitive recording paper according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of the configuration of the pressure-sensitive copying paper according to the embodiment of the present invention, and is a schematic cross-sectional view showing the configuration of the pressure-sensitive copying paper produced in the example. It is a schematic cross section showing an example of the configuration of pressure-sensitive copying paper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure sensitive recording paper 2, 24 Base material 3, 27 Developing layer 10, 23 Lower paper 15, 20 Pressure sensitive copying paper 21 Upper paper 22 Medium paper 25 Color development layer 26 Microcapsule

Claims (4)

A pressure sensitive recording paper comprising a base material and a color developing layer on one side of the base material,
The developer layer is formed of a developer paint containing a binder, a developer and a pigment, the binder contains a modified starch, and the average particle diameter of the pigment is 1 to 10 μm. Yes, pressure sensitive recording paper.   The pressure-sensitive recording paper according to claim 1, wherein the modified starch is at least one selected from oxidized starch, phosphate starch, hydroxyethyl etherified starch and urea phosphate starch.   The pressure-sensitive recording paper according to claim 1 or 2, wherein the pigment contains chestnut-shaped calcium carbonate, and a weak cationic polyamide resin is contained in the developer paint. A pressure-sensitive copying paper using the pressure-sensitive recording paper according to claim 1, 2 or 3.

Images