JP5857392B2 - Near infrared absorbing ink and method for producing the same - Google Patents

Description

  The present invention relates to a near-infrared absorbing ink for the purpose of preventing counterfeiting of securities such as gift certificates, lottery tickets, commuter passes and the like, and more specifically, an infrared absorbing dye and oil contained in at least a resin, a resin It is related with the near-infrared absorptive ink characterized by having high solvent resistance, and its manufacturing method.

  Traditionally, machine-readable code marks such as bar codes and OCR characters are often provided as means for reading information on securities such as stock certificates, bonds, checks, gift certificates, lottery tickets, and commuter passes. In some cases, a code mark is usually formed on a base material surface that reflects light in the near infrared region, using ink that absorbs light in the near infrared region, or ink containing carbon black or the like.

  Utilizing characteristics such as infrared reflection and infrared absorption of white ink and black ink, mechanically readable information is represented by barcode pattern marks using the ink, and this is applied to media etc. The recorded information is read by irradiating this with infrared rays, scanning the mark, and measuring the intensity of the reflected infrared light. Then, visible light is blocked so that information is not read illegally, and a concealing layer that transmits infrared rays is formed to prevent information from being easily read by visible light.

  However, since the infrared absorbing material such as carbon black and leuco dye used in the ink has a light absorbing property even in the visible region, the information pattern is mechanically read by an infrared reader and is also present with the naked eye. Is still unreadable as a means for effectively preventing counterfeiting and alteration such as copying.

  As means for preventing visual observation, heat absorption glass or infrared absorption glass is pulverized as an infrared absorption material, particularly, which itself has little absorption in the visible light region and has absorption in other wavelength regions. It has been considered as an effective means to prevent counterfeiting, tampering, tampering, etc., because it contains pigments in the ink, forms code marks, and has little absorption in the visible light region, making it difficult to see. .

  In printing on securities, printed materials are required to have high resistance to prevent forgery, alteration, tampering, and the like. In some cases, a layer for improving chemical resistance may be provided on the print, but it may not be provided depending on the application. For this reason, the ink itself needs to have chemical resistance. However, many of the conventional infrared absorbing dyes have a problem that a color change appears with time, and near-infrared shielding ability is reduced or disappears.

JP 10-78509 A JP 10-180947 A JP-A 61-154888 JP-A 61-197281 JP-A 61-246091 JP-A-63-37991 JP-A-63-39388 Japanese Laid-Open Patent Publication No. 62-233288 JP-A-63-312889 JP-A-2-43269 JP-A-2-138382 JP-A-2-29685 JP-A-3-43461 Japanese Laid-Open Patent Publication No. 3-77840 JP-A-3-100066 Japanese Laid-Open Patent Publication No. 3-62878 Japanese Patent Application No. 3-338557 Japanese Patent Application No. 3-99730 Japanese Patent Application No. 3-252414 JP-A 61-291651 Japanese Laid-Open Patent Publication No. 61-291651 Japanese Laid-Open Patent Publication No. Sho 62-15260 JP-A-62-132963 JP-A-1-129068 JP-A-1-172458

  The present invention has been made paying attention to the above-mentioned problems, and is excellent in solvent resistance, and particularly has a resistance to effective anti-counterfeiting, falsification, and tampering as a forgery-preventing ink, especially in the near infrared An absorbent ink and a method for producing the same are provided.

The present invention is a mixture of an infrared absorbing dye and a resin dissolved or dispersed in a solvent or water, coated on a substrate, peeled off by means of scraping or sucking, stretching the substrate, mixed with oil, The dispersion of the infrared absorbing dye wrapped in the wet-pulverized resin is mixed with an oil varnish having a spread meter diameter value of 10 mm to 20 mm according to a flow property test described in JIS K5701, and at least included in the resin. An infrared absorbing ink comprising the infrared absorbing dye, an oil varnish resin, and the oil.

The infrared absorbing ink according to claim 1, wherein the dispersion has a kneading degree of 1 μm or less as measured by a kneading degree measurement using a grindometer based on JIS K5701.

The invention according to claim 1 is a process of mixing a curable resin and an infrared absorbing dye, curing the curable resin, and mixing and pulverizing and dispersing the curable resin containing the cured infrared absorbing dye with an oil. A method for producing an infrared absorbing ink, comprising: a step of forming a body; and a step of mixing a dispersion containing a pulverized infrared absorbing pigment and a resin.

The present invention has the following effects from the above configuration and manufacturing method.
The infrared absorbing ink of the present invention can be improved in resistance by wrapping an infrared absorbing dye having low resistance in a resin. In addition, as a manufacturing method thereof, a coating agent in which a resin having high solvent resistance and an infrared absorbing dye are mixed is applied on a substrate and cured, and the cured layer is peeled off, mixed with an oil, and pulverized. Thus, a near-infrared absorbing ink with improved resistance can be obtained.

  The near-infrared absorbing ink of the present invention comprises at least an infrared-absorbing dye wrapped in a resin, an oil component, and a resin.

  The near-infrared absorbing dye used in the present invention is an infrared absorbing material having absorption at 800 nm to 1400 nm, and is preferably selected from phthalocyanine compounds, naphthalocyanine compounds, anthraquinone compounds, diimonium compounds, and cyanine compounds, It is not limited to these. As specific examples, Patent Literature 3, Patent Literature 4, Patent Literature 5, Patent Literature 6, Patent Literature 7, Patent Literature 8, Patent Literature 9, Patent Literature 10, Patent Literature 11, Patent Literature 12, Patent Literature 13, Patent Literature. 14, Patent Literature 15, Patent Literature 16, Patent Literature 17, Patent Literature 18, Patent Literature 19, and the like, phthalocyanines or naphthalocyanines, Patent Literature 20, Patent Literature 21, Patent Literature 22, Patent Literature 23, Patent Document 24, Patent Document 25, and the like.

  The resin enclosing the near-infrared absorbing dye may be a curable resin, and examples thereof include a thermosetting resin, an ultraviolet curable resin, a charged particle beam curable resin, and an electron beam curable resin. What is required is that it has solvent resistance, for example, polypropylene, polyethylene, polyamideimide and the like can be raised, but thermosetting resins such as phenol resin and melamine resin may be used, and are limited thereto. is not.

  As the oil used as the solvent dispersion, those contained in the oil varnish are preferable, and the drying oil is soybean oil, tung oil, linseed oil, etc., and other modified drying oils or semi-drying oils may be used. it can. Furthermore, the solvent used for a varnish may be sufficient and it is organic solvents, such as normal paraffin, isoparaffin, naphthene, alpha-olefin, and other aliphatic hydrocarbons. As the solvent, a high boiling point solvent having a boiling point of 200 ° C. or higher is preferable. For example, there are 0 solvent, 5 solvent, 7 solvent, AF solvent (all manufactured by Nippon Oil Corporation) and the like.

  The infrared absorbing dye described above and a resin dissolved or dispersed in a solvent or water as appropriate are mixed, coated on a substrate, peeled off and pulverized. Peeling from the base material is performed by means such as scraping or suction, stretching of the base material, etc., and then mixed with oil and wet pulverized. The pulverization can be carried out by ordinary means such as a ball mill, a colloid mill, a hammer mill, etc., and may be classified as appropriate. The particles of the infrared absorbing dye dispersed in a resin have a particle size of 1 μm or less. To.

Measurement of the particle diameter of the dispersion of the infrared absorbing dye wrapped in the resin is based on JIS K5701, using a grindometer (particle size measuring instrument) to measure the continuously changing grooves in the depth direction. Put the ink in the gauge board and pull it from the deep position of the groove to the shallow direction with the scraper pressed at an even speed, read the graduation where dense grains began to appear, and if it can not be read, it will be regarded as 1μm or less The particle size was measured. If the value measured by this measurement method is larger than 1 μm, the dispersion state is poor, and when thin printing is performed, particles are conspicuous and have a surface. Since unevenness appears in the portion and the halftone dot of the halftone printing portion becomes rough, the particle size must be 1 μm or less.

  Next, the resin of the oil-based varnish mixed with the dispersion of the infrared absorbing pigment wrapped in the resin includes polyester resin including alkyd resin, petroleum resin, phenol resin, rosin-modified phenol resin, epoxy resin, ketone resin, rosin A rosin derivative, a rosin-modified maleic resin, and the like are preferable. Particularly, examples of the rosin-modified phenol resin include the following. p-Alkylphenol such as p-octylphenol, p-nonylphenol, paraformaldehyde, and rosin are dissolved in toluene, reacted in an acid or alkaline catalyst, and glycerin, pentaerythritol, or rosin is melted at 200 ° C. After the reaction by adding a resole resin, rosin-modified phenol resin esterified with glycerin, or rosin-modified phenol resin obtained by adding resole resin to glycerin ester of rosin, or rosin-modified alkyd resin and phenol resin are reacted. And rosin-modified phenolic resin.

  As the composition of the oily varnish, a ratio of 10 to 50/10 to 60/10 to 70 in terms of weight ratio of resin / oil / solvent and a total of 100 is suitable. One example is rosin-modified phenolic resin / linseed oil / petroleum high boiling point solvent, which is 40/10/50 (weight ratio). The concentrated ink composition of the present invention may be a composition that does not contain a resin and a solvent and is obtained from a drying oil. In addition, a composition obtained by using a resin and a solvent without containing a drying oil, or a composition obtained by using a resin and a drying oil, a resin and a high boiling point solvent may be used. For example, rosin modified phenolic resin / linseed oil (weight ratio 40/60) and rosin modified phenolic resin / petroleum high boiling point solvent (weight ratio 50/50). In addition, a composition obtained by using a resin and a solvent without containing a drying oil, or a composition obtained by using a resin and a drying oil, a resin and a high boiling point solvent may be used. For example, dispersion / rosin modified phenolic resin / linseed oil (weight ratio 10/40/50) and dispersion / rosin modified phenolic resin / petroleum high boiling point solvent (weight ratio 10/50/40). In addition to the above substances, at least lead and manganese borates need to be added as additives as a dryer, but the weight ratio may be 3% or less. In addition, in order to improve printability, non-reactive resins such as wax, petrolatum polyester, epoxy, and triazine resin and surface modifiers may be added, but the additive is about 5% by weight.

  The oily varnish has a viscosity in the range of 100 to 700 (Pa · s, Pascal second) at normal temperature (25 ° C.). Moreover, it is necessary for the flow meter to have a spread meter diameter value of 10 mm to 20 mm according to a flow characteristic test described in JIS K5701. This is a physical property required for the offset method, which is one of the most desired printing methods from the viewpoint of speed, speed, and multicolor printing for security applications. As an ink, it is generally easy to make it soft, but it is difficult to make it hard. If it is a hard ink, it can be softened by dilution or the like, and it is easy to adjust, so that the above viscosity and fluidity are required.

  As an example of the infrared absorbing ink of the present invention, the composition of a dispersion of infrared absorbing pigment wrapped in resin / rosin modified phenolic resin / linseed oil / petroleum high boiling point solvent is 10/40/10/40 ( Weight ratio).

Mixing the dispersion of the infrared-absorbing dye wrapped in the resin with the lithographic ink varnish does not require the kneading of the pigment particles, and the lithographic ink varnish can be uniformly mixed by a mixer to obtain the final ink.
Hereinafter, the present invention will be described in detail by way of examples and comparative examples.

Phthalocyanine dyes EXCOLOR IR-14 (manufactured by Nippon Shokubai Co., Ltd.) 20 parts by weight were dispersed in a solution of 20 parts by weight of a polyethylene resin dissolved in 60 parts by weight of toluene, on a polypropylene film unstretched thickness 25 [mu] m, UV A curable ink is applied at a speed of about 70 m / min, cured by irradiating with ultraviolet rays, and stretched to peel off, mixed with oil, and pulverized with a roll mill to obtain a dispersion. It was. 20 parts by weight of this dispersion and 80 parts by weight of oily varnish No. 0 Solvent H (manufactured by Nippon Oil) having a weight ratio of rosin-modified phenolic resin / soybean oil / petroleum high boiling solvent of 40/10/50 at room temperature Mixing with a disper, an oxidation polymerization type offset ink absorbing infrared rays was obtained. The kneading degree of this ink was 1 μm or less as measured by using a grindometer based on JIS K5701. The spread meter diameter value was 16.0 mm. A test piece was prepared from this ink using an RI tester.

<Comparative example>
10 parts by weight of phthalocyanine dye EEX Color IR-14 (manufactured by Nippon Shokubai Co., Ltd.) is an oily varnish No. 0 Solvent H having a weight ratio of rosin modified phenolic resin / soybean oil / petroleum high boiling solvent of 40/10/50 ( 90 parts by weight of Nippon Oil Co., Ltd. was mixed with a disper at room temperature to obtain an oxidation polymerization type offset ink that absorbs infrared rays. Measurement of the kneading degree of the ink using a grindometer (particle size measuring instrument) with a scale of 1.0 μm based on JIS K5701 was 1.0 μm or less below the measurement limit because no vertical streak appeared. This ink was developed on high-quality paper by an RI tester to prepare a test piece.

The test pieces prepared in Examples and Comparative Examples were measured for the reflectance of infrared ray 840 nm with a spectrophotometer UV-3100 (manufactured by Shimadzu Corporation), and then subjected to a resistance test for the following chemicals. Table 1 shows the results of measuring the reflectivity at 840 nm with the same spectrophotometer after being immersed in the chemicals in Table 1 for 10 minutes. In the comparative example, the reflectance was higher and the absorption was lower than that of the solvent, but it was found that the examples of the present invention were excellent in chemical resistance with no change in the reflectance. Moreover, according to the manufacturing method of this invention, the infrared rays absorption ink composition excellent in chemical resistance can be obtained efficiently.

Claims (1)

  Mixing the curable resin and the infrared absorbing dye, curing the curable resin, mixing the cured curable resin containing the infrared absorbing dye with oil, and pulverizing it into a dispersion; A method for producing an infrared-absorbing ink, comprising: mixing a dispersion containing an infrared-absorbing dye and a resin.