JPH0326669B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a developer ink for pressure-sensitive copying paper using a novel developer. Various forms of pressure-sensitive copying paper are known. In general, it is an application of the fact that a leuco dye (hereinafter referred to as a color former), which is an electron donating substance, and an electron accepting substance (hereinafter referred to as a color developer) react to form a colored substance. In other words, a unit consists of an upper sheet in which a color former is dissolved in a non-volatile solvent and a microcapsule of this solution is applied to the back side of a support, and a lower sheet in which a color developer is applied to the surface of the support. When pressure is applied with the coated surfaces facing each other, the capsules coated on the back side of the top paper break and a solution containing the coloring agent oozes out, which then comes into contact with the color developer coated on the bottom paper and develops color on the copying paper. be. In addition, copying paper in which an inner paper coated with a color developer on the surface of the upper paper is sandwiched between the upper paper and the lower paper to form an upper-middle-lower unit and pressurized in the same manner to record three copies, and the capsule. There is a self-coloring pressure-sensitive copying paper in which color developer and color developer are coated on the same paper surface. These pressure-sensitive copying papers are usually coated with two components, a color former and a color developer, either singly or in combination, over the entire surface of the paper, and if there is a part that you do not want to copy, it is necessary to prevent that part from developing color. They are manufactured either by printing a desensitizing ink to prevent color development, or by applying the above-mentioned two components singly or in combination only to desired areas. The latter manufacturing method mentioned above is a partial printing method, which is generally called a spot printing method. The present invention relates to a letterpress plate used in a spot printing method,
This invention relates to a color developing ink for offset. Conventionally, color developing inks using clays described in Japanese Patent Publication No. 43-28430 are known as color developing inks used in spot printing methods, but these clays do not have sufficient color developing ability due to their attributes. Instead, the amount of coating has to be increased, resulting in an increase in coating thickness, and since strong pressure is applied during storage and use during stacking, coloring also occurs in unnecessary areas, which is undesirable. Next, in order to avoid the harmful effects of these clays,
For example, as described in Japanese Patent Publication No. 49-27134, an improvement has been proposed for developing color inks in which aromatic carboxylic acids or their anhydrides coexist with metal compounds. Further, Japanese Patent Publication No. 42-20144 discloses an ink for flexography and gravure called resin spot ink in which a phenol-formalin resin is dissolved. However, these disclosed
This relates to color developing inks for flexography and gravure. Furthermore, satisfactory properties such as color development, light resistance, and plasticizer resistance have not yet been obtained. As a result of intensive research into color developer inks for letterpress printing and offset printing, the present inventors found that in color developer inks for pressure-sensitive copying paper that are mainly composed of an electron-accepting color developer, a solvent, and a pigment, the color developer is p-
A product obtained by mixing or reacting a condensate obtained by reacting hydroxybenzoic acid with a p-substituted alkylphenol having an alkyl group having 1 to 12 carbon atoms with formaldehyde in the presence of an acidic catalyst with a polyvalent metal compound, Alternatively, by mixing or reacting the condensate with a polyvalent metal compound and mixing it with clay, it is possible to significantly improve the coloring performance, the light fastness of the colored image, and the clear image, and also to prevent light yellowing and nitrogen discoloration of the printed surface. We were able to improve yellowing caused by oxides and further improve discoloration resistance due to plasticizers. Hereinafter, the present invention will be described in detail and specifically. The color developer ink for pressure-sensitive copying paper of the present invention is mainly composed of three components: a color developer, a solvent, and a pigment. First, p-substituted alkylphenols, which are raw materials for forming the color developer that characterizes the present invention,
The conditions that define the reaction product, such as the molar ratio of the p-substituted alkylphenol and p-hydroxybenzoic acid, the formaldehyde source, and the polyvalent metal compound, will be specifically exemplified below. As p-alkylphenol species, substituents are
C ₁ to C ₁₂ (e.g. p-cresol, p-
(ethylphenol, p-isopropylphenol, p-tert _- butylphenol, p-tert-amylphenol, p-tert-octylphenol), preferably _C4-12 . The desired condensate can be obtained by reacting one or more of the above p-substituted alkylphenols in the presence of p-hydroxybenzoic acid. The molar ratio of p-hydroxybenzoic acid and p-substituted alkylphenol used is p-hydroxybenzoic acid/p-substituted alkylphenol=0.1-5, preferably 0.5-3. As the formaldehyde source, any formaldehyde source such as formalin and paraformaldehyde can be used as long as it generates formaldehyde under the reaction conditions.
Examples of the catalyst include phosphoric acid, hydrochloric acid, oxalic acid, p-toluenesulfonic acid, and sulfuric acid. The molar ratio of formaldehyde/[p-substituted alkylphenol + p-hydroxybenzoic acid] is usually
It is 0.4-1, preferably 0.6-0.8. Polyvalent metal compounds include oxides, hydroxides, carbonates, basic carbonates, phosphates, silicates or sulfates of zinc, aluminum, titanium, nickel, cobalt, magnesium or calcium; Zinc is particularly preferred as the metal, and as compounds include oxides, hydroxides, basic carbonates,
In particular, oxides are preferred. The ratio of the polyvalent metal compound and condensate is usually 1:99 to 99:99 by weight.
Although the ratio is appropriately selected from the range of 1, 5:95 to 80:20 is preferable in consideration of the flatness of the resulting copy paper and economical efficiency. When reacting polyvalent metal compounds, the reaction temperature is room temperature or higher and 240°C or lower, preferably 80 to 180°C.
It is. As solvents, those used in ordinary letterpress and offset inks can be used as they are, as well as linseed oil, machine oil, spindle oil, etc.
Glycol solvents disclosed in Japanese Patent No. 51-80410 may also be mentioned. Examples of clays include those having color developing ability, such as kaolin, acid clay, and activated clay. In addition,
These can also be utilized as pigments as described below. Pigments include oxides such as titanium oxide, zinc oxide, magnesium oxide, aluminum oxide, and silicon oxide, hydroxides such as zinc hydroxide and magnesium hydroxide, carbonates such as magnesium carbonate and calcium carbonate, kaolin, and acid clay. Examples include clays such as. Incidentally, the pigment is related to the improvement in suitability during printing, regardless of the presence or absence of color developing ability. Hereinafter, the present invention will be specifically explained with reference to Examples. In the examples, "parts" indicate parts by weight. Example 1 (1) Synthesis of color developer 69 parts of p-hydroxybenzoic acid, 138 parts of p-tert-octylphenol, 37% formalin
61.5 parts, p-toluenesulfonic acid 1 part, and water
53 parts were put into a reaction vessel, and after reacting under reflux for 3 hours,
After adding 21 parts of transparent zinc white and reacting under reflux for an additional hour, the condensate was taken out and solidified. This condensate was reduced to an average particle size of 2 to 3 μm using a dry pulverizer, and was subjected to the following experiment. (2) Preparation of color developer ink for letterpress and offset Color developer obtained in (1) above 10 parts paraffin solvent (average BP 280℃)
20 parts of titanium oxide was added to a mixture obtained by heating and dissolving 15 parts of titanium oxide, and the mixture was made into an ink using three kneading rolls. Example 2 Creation of color developer ink for letterpress and offset 10 parts of the color developer obtained in Example 1 (1) 10 parts of paraffinic solvent (average BP 280°C) 15 parts of paraffin solvent was dissolved in a heated mixture, 10 parts of titanium oxide and 10 parts of kaolin were added. % and made into ink using three kneading rolls. Comparative Example 1 Preparation of color developing ink for letterpress and offset 20 parts of titanium oxide was added to a mixture of 10 parts of p-phenyl-phenol and 15 parts of paraffinic solvent (average BP 280°C) dissolved by heating, and the mixture was made into an ink using three kneading rolls. . Comparative Example 2 Preparation of color developing ink for letterpress and offset 10 parts of p-phenyl-phenol 10 parts of paraffinic solvent (average BP 280°C) were dissolved by heating, and 10 parts of titanium oxide and 10 parts of kaolin were added to the mixture and mixed with three kneading rolls. It was made into ink. Hereinafter, the developer inks prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were printed on 41 g/m ² high-quality paper using a letterpress printing machine so that the amount of smearing (solid content) was approximately 3.5 g/m ² . A color developing sheet was obtained by printing. The test methods and evaluation results (Table 1) of various tests on the obtained color developing sheet are shown. (1) Color development test Commercially available pressure-sensitive recording paper "Mitsubishi NCR Paper-40" was layered with a color developer sheet and passed through a super calendar at a pressure of 10 kg/cm ² to develop color.
After 24 hours, the color density was measured using an optical densitometer with a red filter. Note that the higher the numerical value, the greater the color density. (2) Light resistance test The colored sample obtained in (1) above was irradiated with xenon light for 3 hours using a fade meter, and the density after fading was measured in the same manner. Note that the higher the numerical value, the greater the light resistance. (3) Plasticizer resistance test The colored sample obtained in (1) above was
0.2mm) bag and heated and stored at 60℃ for 1 day and night.
After contacting with a plasticizer contained in vinyl chloride, the blue color density was measured using an optical densitometer with a red filter. Note that the higher the value, the greater the plasticizer resistance. (4) Light yellowing test of uncolored area Irradiated with xenon light for 3 hours in the same way as in (2) above,
Yellowing density was measured using an optical densitometer with a blue filter. The higher the value, the more progressed the yellowing, and the lower the value, the better. (5) Yellowing resistance test due to nitrogen compounds The uncolored developing sheet was left in a container containing 150 ppm of nitrogen compounds for 30 minutes, and then the yellow density was measured using an optical densitometer with a blue filter. The higher the value, the more progressed the yellowing, and the lower the value, the better. The uncolored density is also listed in Table 1 for comparison with yellowing resistance.

[Table] As shown in Table 1 above, the letterpress of the present invention,
Compared to the color developer ink shown in the comparative example, the color developer ink for offset has remarkable properties in terms of color development, light resistance, plasticizer resistance, light yellowing of uncolored areas, and yellowing due to nitrogen oxides. That is clear.

Claims (1)

[Scope of Claims] 1. A color developer ink for pressure-sensitive copying paper mainly comprising an electron-accepting color developer, a solvent, and a pigment, wherein the color developer contains p-hydroxybenzoic acid and a carbon number of 1 to 12.
A letterpress, characterized in that it is a reaction product obtained by mixing or reacting a condensate obtained by reacting p-substituted alkylphenol having an alkyl group with formaldehyde in the presence of an acidic catalyst with a polyvalent metal compound. , color-developing ink for offset. 2. A color developer ink for pressure-sensitive copying paper mainly consisting of an electron-accepting color developer, a solvent, and a pigment, in which the color developer contains p-hydroxybenzoic acid and a carbon atom having 1 to 12 carbon atoms.
A condensate obtained by reacting a p-substituted alkylphenol having an alkyl group with formaldehyde in the presence of an acidic catalyst is mixed or reacted with a polyvalent metal compound, and mixed with clay. Characteristic developer ink for letterpress and offset printing.