JPS609033Y2 - Color developer sheet for pressure-sensitive copying paper - Google Patents

Description

[Detailed description of the invention] The present invention relates to a color developer sheet for pressure-sensitive copying paper, and more particularly to a partially color-developing color developer sheet printed with a color developer ink containing an electron-accepting organic color developer as a main component. .

Pressure-sensitive copying paper generally consists of a top sheet coated with microcapsules containing minute oil droplets containing an electron-donating organic color former and a bottom sheet coated with an electron-accepting developer. They are used as a set by stacking them so that they are facing each other.

In this case, the capsule is destroyed by writing pressure applied from outside during recording or printing pressure from a typewriter, etc., and the oil contained in the capsule is transferred to the color developer surface, resulting in a colored image. .

If a large number of copies is desired, a middle sheet coated with microcapsules and a color developer on both sides is inserted in the middle.

(The various forms of pressure-sensitive copying paper are introduced in detail in the September 1975 issue of 1 Paper Pulp Technology Times.

) In such pressure-sensitive copying paper, in order to obtain a colored image only in the desired area, those printed with a color developer as ink are in practical use, for example, on high-quality paper, medium-quality paper, etc. There are partially color-developing bottom paper, in which developer ink is printed on the base paper, and partially color-developing middle paper, in which developer ink is printed on the base paper surface of the top paper.

The method of printing color developer ink has the advantage that it is easier to obtain a color developer sheet with partial color development than the method of printing the color developer layer with desensitized ink, but due to the special nature of the process. As a result, the following disadvantages occur in terms of quality compared to a color developer sheet obtained by applying a color developer coating liquid using a conventional coater.

That is, (1) the color developing ability of the obtained color developer layer is low, and a clear recorded image cannot be obtained.

(2) When printing developer ink on the base paper surface of top paper, the capsules may be destroyed by the printing pressure, or the solvent in the ink may extract the oil in the capsules. The coloring agent reacts to generate colored stains called ``short stains''.

(3) When printing color developer ink on the base paper side of the rolled top paper and finishing it by offset printing rules, patterns, etc., the color developer printed surface and the capsule layer are in contact with each other and the capsule layer is rolled up. As a result, colored stains called ``roll stains'' occur due to the printing pressure or the roll pressure of the winding roll.

There are some drawbacks that can be recognized. Regarding the disadvantage (1), phenolic resin has superior color developing ability compared to inorganic color developers commonly used as electron-accepting color developers such as activated clay, acid clay, and montmorillonite, and can be dissolved in ink. Although considerable improvements have been made by using organic color developers such as aromatic carboxylic acids and polyvalent metal salts thereof, the situation is still not satisfactory.

Regarding (2) short-circuit stains, methods have been proposed, such as using a special resin as a binder in the developing ink (Japanese Patent Application Laid-open No. 50-64006, JP-A No. 50-54406), but these methods are still not satisfactory. It's not in the condition it should be.

There is no solution to the problem (3).Especially with the recent remarkable increase in printing speed (and the occurrence of '10-color stains is also increasing), organic color developers are being used to increase the color developing ability. Since this phenomenon occurs more markedly when using

The purpose of this invention is to improve all of the above-mentioned drawbacks associated with the method of printing color developer ink, and to provide a color developer sheet that has the same quality level as a color developer sheet obtained by applying a color developer coating liquid with a coater. The goal is to provide the following.

Such an object of the present invention is to provide a first layer on the support 1 which is mainly composed of inorganic and/or organic solid fine particles and an adhesive, and which does not show practical coloring with respect to an electron-donating organic coloring agent.
This is distantly related by providing a coating layer 2 of 1 and further providing a color developing ink layer 3 containing an electron-accepting organic color developer as a main component on the first coating layer 2.

Below is a detailed explanation of each component of this invention.
In the present invention, the first coating layer provided under the color developer ink layer is practical for thermoelectron-donating organic color formers, since the present invention relates to a color developer sheet with partial color development property. The layer must not exhibit significant coloring ability.

The degree to which it does not show practical coloring ability varies depending on the object to be detected in practical use; for example, if the object to be detected is the human eye, the coloring does not appear to the human eye, and if it is an object to be detected by an optical device, It means the concentration below that detected by the optical detector.

Examples of the inorganic solid particles contained in the first coating layer include zinc oxide, zinc hydroxide, aluminum oxide, aluminum hydroxide, titanium oxide, calcium sulfate, barium sulfate, kaolin, calcined kaolin, and clay. ,
Examples include inorganic pigments such as acid clay.

Among these, clays such as kaolin, clay, and acid clay have coloring ability, so depending on the application, they may be surface treated with surface treatment agents such as fatty acid esters, higher alcohols, soybean proteins, metal soaps, etc., or polyethyleneimine, etc. It is necessary to use desensitizing resins such as polyvinyl polydine and styrene/maleic acid copolymer ammonia salt.

Furthermore, alkaline pigments made of salts of strong alkaline metals such as calcium carbonate, calcium hydroxide, magnesium carbonate, and magnesium hydroxide are disclosed in Japanese Patent Application Laid-Open No. 49-109118.
When used in combination with an inorganic color developer as described in the above issue, it contributes to improving the color developer, but when used in combination with a system using an organic color developer as in the present invention, the color developer may actually deteriorate over time. It is excluded from the inorganic solid particles of the present invention.

However, it is of course possible to use alkaline pigments that have been surface-treated as in the case of the clays having color-forming ability.

Examples of the organic solid fine particles include fine particle synthetic polymers obtained by emulsion polymerization or suspension polymerization, synthetic polymers atomized by pulverization, powder mist drying, etc., and particles of starch and modified starch.

Such inorganic and organic solid particles can be used as adhesives, dispersants,
It is preferably applied to the support as an aqueous coating solution by appropriately blending various usual auxiliary agents such as flow modifiers, dyes, antifoaming agents, and the like. It is also possible to apply it to the support as a dispersion coating liquid in an organic solvent such as ethyl, butyl acetate, ethyl cellosol, toluene, hexane, or the like.

Examples of adhesives used in combination with such fine particles in aqueous coating solutions include polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, modified starch, water-soluble polymers such as water-soluble salts of styrene-maleic acid copolymers, and styrene. - Latexes such as butadiene copolymer latex, butadiene and methyl methacrylate copolymer latex are preferably used.

Preferred examples of organic solvent-based adhesives include nitrocellulose, acetylcellulose, ethylcellulose, polyvinyl acetate, polyvinylidene chloride, polyvinyl butyral, and polystyrene.

The combined ratio of solid fine particles and adhesive is not necessarily limited as it varies depending on the material used, but generally solid fine particles 1
The amount of adhesive is in the range of 5 to 100 parts by weight, preferably 10 to 60 parts by weight, based on the pounded weight part.

In the present invention, the coating amount of the first coating layer provided on the support is appropriately selected depending on the composition of the coating layer, the composition of the color developing ink, etc., but is generally 1.0 to 10.0 da. /d, preferably 1.5 Da/d to 5.09/rrt.

The color developing ink layer provided on the first coating layer of the present invention contains an organic color developer as a color developer. For example, benzoic acid, P-tert-methylbenzoic acid, salicylic acid, 3-phenylsalicylic acid,
．． 5-di-tert-butylsalicylic acid, 3-phenyl-5-(α,α-dimethylbenzyl)salicylic acid, 3.
Various aromatic carboxylic acids such as 5-di(α-methylbenzyl)salicylic acid and 2-hydroxy-1-benzyl-3-naphthoic acid, and these together with zinc, aluminum,
Salts with polyvalent metals such as magnesium and cobalt, Special Publication Showa 4
0-930 peak, Special Publication No. 1972-20144, Japanese Patent Publication No. 1973
-14409 etc., phenol resins such as phenol-aldehyde resins, phenol-acetylene resins, and polyvalent metal salts thereof, maleic acid-rosin resins, styrene, ethylene or vinyl methyl ether, and maleic anhydride. Acidic polymers such as copolymers with
Examples include polymers of aromatic carboxylic acids and aldehydes or acetylene and polyvalent metal salts thereof, which are described in Japanese Patent Publication No. 52-8216 and Japanese Patent Publication No. 52-1326. and polyvalent metal salts thereof are preferably used.

The color developing ink containing such an organic color developer is prepared by appropriately blending various usual auxiliary agents such as pigments, adhesive resins, dispersants, dyeing agents, antiblocking agents, and plasticizers, and is then applied to a volatilization method such as a flexographic or gravure type. Various known types of color developing ink such as solvent type, nonvolatile solvent vehicle type such as letterpress or lithography, oxidative polymerization type, ultraviolet curing type, and cold set type are printed on the first coating layer, but preferably flexographic or It is printed using volatile solvent-based ink such as gravure type.

The printing coating amount is adjusted as appropriate depending on the composition of the first coating layer, the composition of the color developing ink, etc., but it is generally 0.1% as a non-volatile content.
5.0 g/lyf, preferably 0.3 to 3.0 g/lyf. Of
/d Printed.

The present invention will be explained in more detail with reference to Examples below, but is not limited thereto.

Note that unless otherwise specified, parts and % indicate parts by weight and % by weight, respectively.

Examples 1 to 6 A coating liquid mainly composed of solid fine particles and an adhesive as shown in the table was applied to one side of a high-quality paper of 40 f/rd to a dry weight of 4. The coating was coated to obtain Of/d and dried to obtain a support a.

After supercalendering the support A, a microcapsule coating liquid of 5 g/- in dry weight was applied to the back side which was not coated with the first coating layer, and dried to produce a top paper, which was used as a support. did.

Naori Pucelle coating liquid is crystal violet lactone 2
100 parts of alkylnaphthalene dissolved in 2 parts of gelatin
5 parts of gum arabic and 25 parts of gum arabic were used to form microcapsules having an average particle diameter of 6 μm, and 25 parts of pulp powder and a modified starch aqueous solution were added thereto in two widths in terms of solid content.

On the first coating layer of the above support a, 3Cs1 zinc 3,5-di(α-methylbenzyl)salicylate, 6 parts colloidal aluminum oxide, 2 parts zinc oxide, 15 nitrocellulose
4 parts of ethanol and 4 parts of ethyl acetate were added to a mixed solvent of 4 parts of ethanol and 4 parts of ethyl acetate, and the resulting color developing ink was dispersed in a ball mill.
Diluted with a (1:1) mixed solvent of ethyl and printed on a business form printing machine with a coating weight of 1. Flexographic printing was performed to obtain a color developing sheet a (bottom sheet) so as to obtain Of/d.

Further, in the same manner as above, a developer ink is printed on the first coating layer of the support using a business form printing machine, and a design is further offset printed, and the developer sheet B [middle layer] is finished by folding and winding. Sheet] was obtained.

The color developer sheet obtained was evaluated for color developer ability, short stain, and roll stain as follows, and the results are also listed in the table.

Regarding the color developing ability, the top sheet obtained by applying the above color developer sheet A [bottom sheet] and the capsule coating liquid to 40 g/lyl'' high-quality paper at a dry weight of 5fld was layered in one layer at a pressure of 300 kg/al. The density of the colored image was measured using a Macbeth densitometer.

Regarding short stains, the degree of staining was visually determined for a folded and finished sample of the developer sheet b (middle sheet).

As for roll stains, the degree of staining was visually determined for a rolled and finished sample of the developer sheet b (middle sheet).

Comparative Example 1 A color developing sheet was obtained in the same manner as in the example except that 40 g/d high quality paper without the first coating layer was used, and a quality test was conducted.

As is clear from the results in the table, the color developing sheet of the present invention has good resistance to short stains and roll stains, and also exhibits excellent color developing ability. It maintained the same quality as colored sheets.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of the color developing sheet according to the present invention. In the figure, 1 is a support, 2 is a first coating layer, 3 is a developing ink layer, and 4 is a capsule coating layer.

Claims (1)

[Claims for Utility Model Registration] ■ On the support 1, zinc, aluminum, titanium oxides, hydroxides, calcium sulfate, barium sulfate, kaolin, calcined kaolin, clay, and/or organic solid fine particles. The first coating layer 2 has a first coating layer 2 that does not show practical coloring against an electron-donating organic coloring agent whose main component is an adhesive, and an electron-accepting organic coloring agent is further formed on the first coating layer 2. A color developer sheet for pressure-sensitive copying paper, characterized in that a color developer ink layer 3 containing a color developer as a main component is partially provided. 2. The color developer sheet for pressure-sensitive copying paper according to claim 1, wherein the electron-accepting organic color developer is at least one of aromatic carboxylic acids and polyvalent metal salts thereof.