JPH0338377A - Coupler sheet for pressure-sensitive recording - Google Patents

Abstract

PURPOSE:To obtain a coupler sheet for pressure-sensitive recording having excellent recording properties and printability by providing the coefficient of oil absorption of a specific value or more to diisoproplynaphthalene. CONSTITUTION:One drop 7 of diisopropylnaphthalene is vertically dripped on the coupling recording layer 4 formed on the support 5 of the coupler sheet 3 placed on the support stand 2 on a black table 1 using a microsyringe 6. After dripping, the coupling recording layer is irradiated with the light from an illumination light source 8 and, by visual observation, the time required until the oil penetration part having a diameter of 1cm formed by the penetra tion of oil in a sheet is uniformly transparentized is measured. The coefficient (a) of diissopropylnaphthalene absorption of the coupler sheet is calculated according to formula (1) and, in case of 0.01cm/sec or more, the developed color density, color forming speed and printability of the coupler sheet can become statisfactory and the oil absorbing capacity of the coupler sheet is high and the dye-containing oil discharged by the destruction of microcapsules is rapidly and efficiently absorbed in the coupler sheet to enhance color forming capacity.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a color developing sheet for pressure-sensitive recording.

More specifically, the present invention is used to record an image formed by developing the dye, which is used by being overlaid on a dye sheet containing a substantially colorless dye that develops color when it comes into contact with an acidic substance. This invention relates to a color developing sheet for pressure-sensitive recording.

[Conventional technology]

Pressure-sensitive recording materials, also called carbonless paper, are essentially colorless sheets of paper (dye sheets) whose backsides are coated with microcapsules containing colorless dyes, such as leuco dyes, which develop color when they come into contact with acidic substances. , consists of a lower paper (color developer sheet) whose surface is coated with a color developer that develops color by contacting the colorless dye, and if necessary, a color developer layer is applied to the surface between the upper and 1000 sheets. One or more inner sheets coated with a layer of dye microcapsules on the back side may be inserted. On top of this,
By stacking the middle and bottom papers and applying pressure from a pen or printer, etc., the dye microcapsules on the top paper are destroyed, the dye comes into contact with the color developer on the bottom paper, and the dye on the bottom paper is colored. A colored image can be formed on the color developer layer, and 1
If more than one sheet of paper is used, it is possible to make multiple copies at a time.

In general, the performance required for a color developing sheet for pressure-sensitive recording includes a high color development rate of 31 degrees with respect to colorless dyes, a fast color development speed, and good light resistance, chemical resistance, and water resistance of colored images. The developer layer must not yellow or deteriorate due to light or nitrogen oxides in the air, and the developer's ability to develop color against colorless dyes must not deteriorate during storage. , and offset of the developer layer surface,
Good suitability for printing with letterpress, flexo, etc. can be mentioned.

Generally, inorganic color developers such as acid clay and abatalgite have been used as color developers for pressure-sensitive recording.
These had the disadvantage that the colored images formed by them faded due to light or water. Known methods for improving these drawbacks include adding zinc oxide to an inorganic color developer (Japanese Patent Publication No. 46-9290) and adding rhodanate (Japanese Patent Publication No. 48-12254). .

However, these improvement methods have not yielded satisfactory results. Organic acid color developers were developed as color developers that do not have the above-mentioned drawbacks of inorganic color developers, and specifically, phenolic resin color developers (Japanese Patent Publication No. 42-20144)
Polyvalent metal salts of salicylic acid derivatives (Japanese Patent Publication No. 51-2517
4 etc.), polyvalent metal salts of salicylic acid-containing copolymers (JP-A-62-176875.63-53092゜63-186
729, etc.), and polyvalent metal salts of terpene phenol resins (Japanese Patent Application Laid-Open No. 19486/1986). However, these organic acid color developers have a slow color development rate,
Furthermore, since ink receptivity and ink drying speed are insufficient, troubles are likely to occur during printing when used.

[Problem to be solved by the invention]

The present invention eliminates the above-mentioned drawbacks of conventional color developer sheets, provides high color density, fast color development speed, and causes problems such as uneven ink coverage and stains due to ink transfer during printing. The object of the present invention is to provide a color developer sheet for pressure-sensitive recording that has excellent recording properties and printability without causing any problems.

[Means to solve the problem]

The color developing sheet for pressure-sensitive recording of the present invention comprises a sheet-like support;
Formed on one surface of this sheet-like support, is an electron-accepting material that can develop a color when it comes into contact with a substantially colorless electron-donating dye. A color developer sheet for pressure-sensitive recording having a color developer recording layer containing a pigment and a pigment, the color developer sheet having a color developer layer containing 0.0 to diisopropylnaphthalene.
Oil absorption coefficient a of 1 cm/sec or more (however, diisopropylnaphthalene is an oil for microcapsules containing an electron-donating dye, and a is a drop of the oil on the surface of the color developer recording layer of the color developer sheet using a microsyringe. The time (seconds) required for the oil-penetrated area with a diameter of 1c+n formed by this oil to become uniformly transparent in the color-developing sheet. This is the value obtained by dividing the sheet thickness (cm). In order to impart the above-mentioned oil-absorbing properties to the 8JI color sheet, l) when coating and forming the color developing recording layer, the migration of the binder to the surface of the coating layer must be suppressed as much as possible.

2) The amount of pigment in the developing layer is 6% based on the total solid weight.
The content should be 5% or more, and the amount of a water-soluble binder with strong film-forming properties, such as polyvinyl alcohol, should be 10% or less.

3) The content of a hydrophobic binder with strong affinity for oil, such as styrene-butadiene latex, is set to 50% or more of the total solid molecule fiffl of the binder to increase the oil absorption capacity.

4) To increase oil absorption capacity, JIS-5101
Organic or inorganic pigments with an oil absorption of 35 cc/100 g or more as described in
% or more.

It is preferable to use a method such as

In the present invention, the diisopropylnaphthalene oil absorption coefficient is measured by the following method.

In FIG. 1, as shown, a microsyringe 6 is placed on the color developer recording layer 4 formed on the support 5 of the color developer sheet 3 placed on the support stand 2 on the black table 1. The oil for microcapsules used is 1i7 of diisopropylnaphthalene (trademark: KMC-113, manufactured by Kureha Chemical Co., Ltd.).
Drop vertically. After dropping, apply light from the illumination light A8 and visually check the time required for the oil to permeate into the sheet and make the oil permeated area with a diameter of 1 cm uniformly transparent using a stopwatch. Accurately measure to the order of 0, 1 second. The oil absorption system number (a) is defined by the following formula, and the average value of 10 measurements is taken and the significant figure is 2.
Display in digits.

The oil absorption number a for diisopropylnaphthalene (oil) of the color developer sheet measured in this way was 0.01 c
m / sec or more, the color density of the color developer sheet,
The coloring speed, speed and printability are satisfactory. In other words, when the oil absorption number a is 0.01 cm/sec or more, the oil absorption capacity of the color developing sheet is large, and the dye-containing oil released by the destruction of the microcapsules is rapidly absorbed.
It is believed that the color development performance is improved because it is efficiently absorbed by the color developing sheet, and it is also believed that the printing permeability is improved because it efficiently absorbs dampening water or ink during printing. If the absorption coefficient a is smaller than 0.01 cm/sec, the oil of the color developer sheet, the printing ink,
The absorption of bleaching water, etc. becomes slow, and the above properties become unsatisfactory.

In the color developing sheet of the present invention, the support is formed of wood-free paper, medium-quality paper, coated paper (including lightly coated paper, lightweight coated paper, and art paper), and has a basis weight of 20 to 20
Preferably, it is 0 g/nf.

In the color developer sheet of the present invention, the color developer recording layer formed on one surface of the sheet-like support contains a color developer, a white pigment, and a binder, and has a weight of 2 to 10 g/rrT. It is preferable that

As the color developer used in the present invention, any organic acidic substance commonly known as an organic acid color developer can be used, such as P-phenylphenol novolak disclosed in Japanese Patent Publication No. 42-20144. [Novolac-type phenolic resins such as 4-fats, P-octylphenol novolac resins, modified phenolic resins such as phenol-acetylene resins, and polyvalent metal salts thereof; Benzoic acid, nitrobenzoic acid, P-tert-butylbenzoic acid, 4-methyl-3-nitrobenzoic acid, P-isopropylbenzoic acid, 2,5-dinitrobenzoic acid, as described in No. 49-55410, etc. Benzoic acid, m-hydroxybenzoic acid, P-hydroxybenzoic acid, 2-hydroxy-1-benzyl-3-naphthoic acid, ■-benzoyl-2-hydroxy-3-naphthoic acid, 3-hydroxy-
5-cyclohexyl-2-naphthoic acid, salicylic acid, 5
-tert-butylsalicylic acid, 3-phenylsalicylic acid, 3-cyclohexylsalicylic acid, 3-methyl-5-
tert-butylsalicylic acid, 3.5-tert
-butylsalicylic acid, 3-methyl-5-benzylsalicylic acid, 5-cyclohexylsalicylic acid, 3-methyl-5
-Isoaterusalicylic acid, 3.5-di-5ec-butylsalicylic acid, 3-phenyl-5-(α,α-dimethylbenzyl)salicylic acid, 3-cyclohexyl-5-(α,
α-Dimethylbenzyl)salicylic acid, 3-(α,α-dimethylbenzyl)-5-methylsalicylic acid, 3.5-dicytylohexylsalicylic acid, 3.5-di(α-methylbenzyl)salicylic acid, 3゜5-dimethylbenzyl)salicylic acid, (α, α-dimethylbenzyl) salicylic acid, 3-(α-methylbenzyl)
- Aromatic carboxylic acids such as 5-(α,α-dimethylbenzyl)salicylic acid and 4-methyl-5-cyclohexylsalicylic acid, and polyvalent metal salts of these organic acid compounds; described in JP-A-63-132857 Metal salts of oligobenzylated aromatic hydroxycarboxylic acids, such as those disclosed in JP-A-63-19486; polyvalent metal salts of carboxy-modified terpene phenol resins, as disclosed in JP-A-63-19486; JP-A-48-8215 salicylic acid nobotic resin disclosed in; and JP-A-62-176875
, JP 63-53092, and JP 631867
Copolymers of salicylic acid with compounds such as alkoxyxylene, trialkylhenzene, and styrene derivatives, as disclosed in No. 29 et al., and polyvalent metal salts thereof can be mentioned.

The color developer used in the present invention may be composed of only one type of the above-mentioned acidic substances, or may be composed of two or more of them.

Generally, the content of the color developer in the color developer recording layer is preferably 5 to 70% based on the total solid weight of the color developer recording layer.

Examples of the white pigments contained in the color developing recording layer of the present invention include heavy and light calcium carbonate, kaolin, zinc oxide, titanium oxide, zinc hydroxide, aluminum ξium silicate, calcium silicate, calcined kaolin, and hydroxide. One or more of aluminum, talc, etc. can be used.

Generally, the content of the white pigment in the color developing recording layer is preferably 60% by weight or more based on the total solid weight of the color developing recording layer.

Examples of the binder contained in the color developing recording layer of the present invention include carboxymethyl cellulose, gelatin, hydroxyethyl cellulose, oxidized starch, acetate starch, phosphate starch, hydroxyalkylated starch, polyvinyl alcohol, and polyacrylic acid. Water-soluble binder; and styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylic acid (methacrylic acid)
Examples include latex such as ester polymers and vinyl acetate copolymers, and these may be used alone or in combination of two or more.

The color developing recording layer of the present invention may contain conventional additives, such as fluorescent brighteners and lubricants, as necessary, and may also contain water-resistant agents, etc., as necessary. It may also be blended.

〔Example〕

The present invention will be further explained below with reference to Examples. In addition, in the following Examples and Comparative Examples, upper paper (dyed capsule sheet) prepared by the following method was used to form colored images.
It was used.

8 parts by weight of Keishika Crystal Hioresotolactone was dissolved in 200 parts by weight of diisopropylnaphthalene, which was then encapsulated with a urea-formalin polymer wall membrane.

Next, to 100 parts by weight of an aqueous slurry containing dye capsules at a concentration of 50% by weight, 10 parts by weight of a 10% oxidized starch aqueous solution was added.
0 parts by weight, 20 parts of fine cellulose powder, and 20 parts of water
A dye capsule coating solution was prepared by mixing 0 parts by weight.

This coating solution was coated on one side of a support made of base paper with a basis weight of 53 g/rrf so that the coated amount after drying was 5 g/n, and this was dried to prepare a top paper.

A high-quality paper with a weight of 153 g/rrf and a thickness of 65 μm was used as a sheet-like support. In 20 parts by weight of water, add calcium carbonate (trademark: Tunenx E, manufactured by Shiraishi Kogyo Co., Ltd., citron absorption amount: 43 m1/100 g, 60% Ito), and zinc oxide (Zinc White No. 3, manufactured by Hakusui Chemical Co., Ltd., oil absorption FF114).
d/100g60% liquid) in the amount listed in Table 1,
Next, 25 parts by weight of a 40% emulsion of P-phenylphenol resin was added as a color developer while stirring.

Next, add styrene butadiene latex (solid content 50%) and oxidized RI (15% water i
B solution) and a mixture of polyvinyl alcohol (1-05, Nippon Gosei Kagaku, 15% aqueous solution) having the composition shown in Table 1 were added to prepare a coating solution for a color developing recording layer. This coating liquid was applied to one side of the support so that the amount of coating after drying was 6 g/nr while controlling the movement of the binder to the surface of the coating layer. These color developing sheets were used to test their color development performance and printability.The test method and quality evaluation method were as follows.

(2) Color development density: The color development sheet combined with the upper paper was passed between pressurized rolls and then stored in a dark place, and the color density 24 hours later was measured using a Machess reflection quadmeter.

■ Color development speed Two color development density: Measure the density (DL) after 30 seconds of the developing sheet developed using the same procedure as the color development density using a Mapibes reflection densitometer, and calculate the density after 24 hours (color development rate when D2 is set as 100). Expressed in (%).One color rate (%) = (D
t/D2. ) xiOO■ Offset printing suitability: R
The printing was carried out using a type I-II printing tenter (manufactured by Mei Seisakusho).

■ Ink receptivity: Ink receptivity was evaluated using K&N Ingyu (K&N Inc.).

The off-cent printing suitability and ink receptivity were evaluated as C5 below.

Grade 5: Extremely excellent.

Grade 4: Excellent.

Grade 3: Average.

Grade 2: Poor.

Grade 1: Poor.

The test results are shown in Table 2.

The same operations as in Example 1 were performed on two comparison groups. However, the pigments and binders listed in Table 1 were used. In addition, when coating and drying the coating liquid for the color developing recording layer, rapid drying conditions were used (4) to facilitate the movement of the binder to the surface of the coating layer. The test results are shown in Table 2.

[Effects of the Invention] The color developing sheet for pressure-sensitive recording of the present invention has a specific absorption/extraction coefficient a, and has excellent color density, color development speed, and printability. be.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an apparatus for measuring the oil absorption coefficient a of the color developing sheet of the present invention. l...Black table, 2...Support, 3...
- Color developer sheet, 4... Color developer recording layer, 5... Support, 7... Droplet, 6... Microsyringe, 8... Illumination light source.

Claims (1)

[Claims] A sheet-like support and an electron-accepting organic acid substance formed on one surface of the support rod and capable of developing a color when it comes into contact with a substantially colorless electron-donating dye. A color developer sheet for pressure-sensitive recording having a color developer recording layer containing an agent and a pigment, the color developer sheet comprising: diisopropylnaphthalene;
Oil absorption number a of 0.01 cm/sec or more (however, diisopropylnaphthalene is an oil for microcapsules containing an electron-donating dye, and a is the color development record of a color development sheet using a microsyringe to add a drop of the previous oil. The time (seconds) required for the oil to permeate into the color developer sheet by dropping it perpendicularly to the layer surface and to make the oil-penetrated area with a diameter of 1 cm uniformly transparent. thickness(
A color developer sheet for pressure-sensitive recording, characterized in that it has a value obtained by dividing cm).