JPS6341750B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to desensitizers. More particularly, the present invention relates to a desensitizer for suppressing or blocking the coloring function in carbonless pressure-sensitive copying paper using an electron-accepting compound or solid acid for coloring a colorless color former. Generally, pressure-sensitive copying paper consists of paper coated with an electron-donating leuco dye encapsulated in fine capsules and paper coated with an electron-accepting substance or solid acid. When pressurized, the capsule in the pressurized area is destroyed and the leuco dye develops color. The desensitizer is used for the purpose of suppressing or preventing color development by applying it in advance to areas where color development is unnecessary on either the surface coated with the electron-accepting substance or the electron-donating substance. Capsules containing electron-accepting substances and electron-donating substances are uniformly applied to the entire surface of the paper, so it is widely used to apply a desensitizer to either side using a printing machine or the like to remove unnecessary areas. It is. Clay minerals such as acid clay, bentonite, attapulgide, zeolite, and kaolin are known as electron-accepting solid acids. Also, known electron-donating color formers include crystal violet lactone, rhodamine anilinolactone, malachite green lactone, benzoyl leucomethylene blue, Michler's hydrol, and N-allyl leuco auramine. Conventionally known desensitizers include Japanese Patent Publication No. 46-29546;
Polyhydroxy compounds such as those found in Japanese Patent Publication No. 49-19647, Japanese Patent Publication No. 48-6805, etc., Japanese Patent Publication No. 44-27255,
Amine compounds such as those found in Japanese Patent Publication No. 45-21448, hetero compounds such as those found in Japanese Patent Publication No. 33-3921, Japanese Patent Publication No. 15513-1973, etc., Japanese Patent Publication No. 52-156010,
There are polyether compounds such as those found in JP-A-53-97511. Most of these desensitizers are strongly hydrophilic substances and are therefore printed by letterpress printing presses.
It was difficult to use printing machines other than letterpress printing machines. The ability to print desensitizers on printing presses other than letterpress printing presses provides various advantages. For example, if it becomes possible to print with an offset lithographic printing machine, compared to printing with a conventional letterpress printing machine,
(1) Since the ink is offset, the ink buildup is uniform. (2) The printing pressure is applied evenly over the entire surface of the plate, so there is less destruction of the paper microcapsules. (3) Plate making is easy. (4) Printing speed is faster. Large (5) Beautiful printing finish
(6) Since printing presses are widely used in general, we can expect advantages such as high demand. Attempts have been made to print desensitizers using wet offset printing machines, for example, using alkoxyl nucleophilic compounds as desensitizers, but conventional desensitizers have poor printability and anti-bleed properties; The desensitizing effect was also not sufficient. Although attempts have recently been made to print desensitizers by waterless lithographic printing, there has been a strong desire for a desensitizer that can be printed using conventional wet offset printing machines. As a result of intensive research into desensitizers that can be printed not only on letterpress printing machines but also on printing machines other than letterpress printing machines, the present inventors came to invent the desensitizer with excellent desensitizing effects of the present invention. It is something. That is, the desensitizer of the present invention is a desensitizer comprising a product obtained by addition reaction of rosin amine and alkylene oxide or styrene oxide. The present invention has an excellent desensitizing effect on pressure-sensitive copying paper such as carbonless copying paper, and there is no bleeding of the desensitizer to areas where it is not printed, and is applicable not only to letterpress printing but also to printing methods other than letterpress printing. The object of the present invention is to provide a desensitizing agent that has excellent printability during printing, is free from yellowing and odor problems that are disadvantageous to conventional desensitizing agents, and is easy to synthesize. The printing ink using the desensitizer according to the present invention can be printed by various printing methods such as offset printing, flexo printing, etc. in addition to conventional letterpress printing. It has the following advantages. For example, when a printing ink made using the desensitizer according to the present invention is printed using a wet offset printing machine, the printing effect is excellent and the drying properties are also particularly excellent, making it possible to speed up printing. It is easy to make plates and can save a lot of labor. When printed with an ink prepared using the desensitizer according to the present invention, a printed matter with good writability and inconspicuous printing can be obtained. The rosin amine according to the present invention is a primary amine derived from the resin acid contained in rosin.
The main component is dehydroabiethylamine, which has the structure shown below. The alkylene oxide used in the present invention includes ethylene oxide, propylene oxide, butylene oxide, etc., but ethylene oxide and propylene oxide are particularly preferred from the viewpoint of desensitizing effect. The number of moles of alkylene oxide or styrene oxide added is most preferably 1 to 100 moles in the case of ethylene oxide or propylene oxide, and 1 to 20 moles in the case of styrene oxide, per mole of rosin amine.
If the number of moles is more than or less than this, the printing effect and desensitization effect tend to deteriorate. Depending on the purpose, desired additives such as a drying accelerator, other varnishes, solvents, pigments, etc. can be appropriately added to the desensitizer of the present invention to the extent that the desensitizing effect is not inhibited. The present invention will be explained below with reference to Examples. Example 1 Amine D (manufactured by Hercules, USA) 28.7 g (approx.
0.1 mol) and propylene oxide (58 g (1.0 mol)), 30 parts by weight of titanium oxide (rutile) and 10 parts by weight of mineral oil were mixed,
A desensitized ink was prepared by kneading in a ball mill for 24 hours. The obtained desensitized inks were printed on commercially available carbonless pressure-sensitive copy paper using an offset printing tester so that the coating amount was 5.0 g/m ² . Desensitizing inks containing the following addition reaction products were prepared and printed in the same manner.

[Table] Comparative example 1 Polyethylene glycol (molecular weight approximately 400)
(PEG400, manufactured by Sanyo Chemical Industries, Ltd., hydroxyl value 250) 30
A desensitizing ink was prepared by uniformly mixing 30 parts by weight of linseed oil-modified alkyd resin, 10 parts by weight of mineral oil, and 30 parts by weight of titanium oxide (rutile) using a three-roller mill. The obtained desensitized ink was printed using an offset printing tester on the inner sheet of commercially available carbonless pressure-sensitive copying paper so that the coating amount was 5.0 g/m ² . Comparative Example 2 Fine particles were added to 80 parts by weight of a varnish consisting of 67% by weight of ethoxylated nonylphenol (desensitizer), which is a type of alkoxylated nucleophilic compound, 30% by weight of rosin esterified with glycerin, and 3% by weight of mineral oil. A desensitizing ink was prepared by kneading 3 parts by weight of silica, 12 parts by weight of calcium carbonate, and 5 parts by weight of titanium oxide (rutile) in a ball mill for 24 hours. The obtained desensitized ink was printed on commercially available carbonless pressure-sensitive copy paper in the same manner as in Comparative Example 1. Next, test methods for desensitization effect, bleed resistance, and printability will be shown. [Test method] Color test Using the above printing paper, apply 100% to a sphere with a diameter of 0.8 mm.
Copying (color development) was carried out by applying a load of 100 g and moving at a speed of 5 m per minute. The color development results are shown in Table 1, and the numerical values indicate the reflective visibility values (visual density abbreviation: Vis, D) measured with a microdensitometer.

[Table] Bleed resistance test The above printed material and non-desensitized carbonless pressure-sensitive copying paper were stacked together and placed under a load of 10 g/cm ² in a constant temperature and humidity room at a relative humidity of 90% and a temperature of 20°C. After allowing the prints to stand for several months, a color development test was conducted on the printed matter and the non-desensitized carbonless pressure-sensitive copying paper. The results are shown in Table 2.

【table】

[Table] Printing suitability test Printing suitability was comprehensively judged by ease of printing using an offset printing tester. The results are shown in Table 3.

【table】

[Table] ○: Good △: Slightly poor ×: Poor From the results shown in Tables 1 to 3, it can be seen that the desensitizer according to the present invention is excellent in desensitizing effect, bleed resistance, and printability.

Claims (1)

[Claims] 1. A desensitizer comprising a product obtained by addition reaction of rosin amine and alkylene oxide or styrene oxide.