JP2008080591A - Offset printing object excellent in lightfastness, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an offset printing object excellent in lightfastness and its manufacturing method and to expand the application of the offset printing object by enabling the use of the offset printing object in the open air which has been thought to be improper up to now. <P>SOLUTION: The offset printing object constituted by forming at least one or more layers of printing layers on the face to be printed of the base material by offset printing is constituted by forming the respective printing layers in a thickness of at least 2 μm using ink containing 5 to 35% of pigments mainly constituted of particles of particle size of 2 to 9 μm by ink solid weight ratio and is constituted so that the total thickness of at least one layer of printing layers formed on the face to be printed becomes 4 μm or more. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an offset printed matter having excellent light resistance and a method for producing the same, and more particularly to a technique for obtaining a printed matter having excellent light resistance while securing a high-quality pattern by offset printing.

  Conventionally, by applying various printing methods such as offset printing, flexographic printing, gravure printing, screen printing, digital printing, etc. to single color printing or multicolor printing (for example, color printing), the desired printed matter can be obtained. Among them, offset printing has a high printing speed and high productivity. In addition to being able to express thin patterns, it is easy to produce high-quality prints. It has been widely used because it has the feature that it can be obtained.

  And in such printed matter, in addition to being used for various applications such as normal publishing, commercial use, office use, etc., it is also used for packaging, industrial use such as surface decoration for articles or parts, display use, etc. However, among them, outdoor posters and over-the-counter product packages, display panels and decorative panels for vending machines, display panels and decorative panels for automobile interior parts, and displays for home appliances. Panels and decorative panels are required to have sufficient light resistance so that printed pictures (including letters and figures) do not fade under the influence of strong light such as sunlight. Yes.

  For this reason, in order to improve the light resistance of the printed matter, the light resistance of the ink used for each printing has been studied, and in particular, the use of an excellent light resistance as a pigment in such ink has been generally adopted. However, even when printing with a light-resistant ink using a pigment having such excellent light resistance, the offset printed material does not have sufficient light resistance unlike other printed materials. For this reason, it has been conventionally avoided to be used as inappropriate in outdoor and automobile applications.

  However, various attempts have been made to improve the light resistance of offset printed matter. For example, in Japanese Patent Application Laid-Open No. 11-58923 (Patent Document 1), water using a printing plate that does not require immersion water is used. In the no offset printing method, printing using UV ink, IR ink, and EB ink improves productivity and reduces waste paper without losing the advantages of waterless printing, and the tone is good. It has been clarified that printing that sufficiently satisfies the required quality is possible in terms of friction resistance, light resistance, and chemical resistance. In addition, in Japanese Patent Application Laid-Open No. 2001-240739 (Patent Document 2), an offset comprising a polyurethane resin emulsion containing a polycarbonate chain or a polycarbonate chain and a polyester chain in the molecule and having an average particle diameter of 3.0 μm or less. It is clear that a resin composition for printing materials has been clarified, and by using this, it is possible to provide a high-definition offset printing material having excellent weather resistance and discoloration, durability at a practical level, and productivity. Has been.

  However, although all of the proposed technologies mention the light resistance of the offset printed material, it is not intended to improve the light resistance of the offset printed material because it is not the main purpose. For this reason, it has been difficult to apply to outdoor use or the like where it is exposed to strong light, or for applications where high light resistance is required.

JP 11-58923 A JP 2001-240739 A

  Here, the present invention has been made in the background as described above, and the problem to be solved is to provide an offset printed matter with extremely excellent light resistance and a method for producing the same. Also, it is an object of the present invention to make it possible to advantageously use the offset printed matter, which has been regarded as inappropriate from the past, and to expand the application of the offset printed matter.

  In the present invention, in order to solve such a problem, an offset printed matter in which at least one printed layer is formed by offset printing on a printing surface of a substrate, the printed layer Is formed in a thickness of at least 2 μm or more using an ink containing a pigment mainly composed of particles having a particle diameter of 2 to 9 μm at a ratio of 5 to 35% by weight of the ink solid content. An offset printed matter excellent in light resistance, characterized in that the total thickness of at least one or more printed layers formed on the printing surface is 4 μm or more, It is what.

  In addition, according to one of the desirable modes of the offset printed matter according to the present invention, the offset printing is performed using a lithographic printing plate.

  According to another preferred embodiment of the present invention, a plastic sheet is used as the substrate, and in that case, advantageously, the plastic sheet is a transparent or translucent sheet, In addition, at least one printed layer is formed on the back side of the transparent or translucent sheet.

  Further, in the present invention, the offset-printed plastic sheet is advantageously press-molded into a desired shape.

  In such a press-molded offset printed matter, it is desirable that the image given by the print layer is expressed by FM screening using a spot diameter of 10 to 30 μm.

  The gist of the present invention is also a surface decorative material characterized in that an offset printed matter obtained as described above is used, and a resin layer having a predetermined thickness is integrally formed on the back side thereof. It is what.

  Furthermore, in the present invention, there is provided a method for producing an offset printed matter in which at least one printed layer is formed on a printing surface of a base material, which is mainly composed of particles having a particle diameter of 2 to 9 μm. The printed layer is formed in a thickness of at least 2 μm or more by offset printing using an ink containing 5 to 35% of the ink solid content weight ratio, and formed on the printed surface. The gist of the method for producing an offset printed matter having excellent light resistance, wherein the offset printing operation is performed so that the total thickness of the at least one printed layer is 4 μm or more is also provided. It is one of them.

  In addition, according to one of the desirable aspects of the manufacturing method of the offset printed matter according to this invention, such offset printing will be implemented using a lithographic printing plate.

  According to another preferred embodiment of the method for producing an offset printed material according to the present invention, the offset printing is performed at a printing speed not exceeding 60 m / min.

  Furthermore, according to another desirable aspect of the method for producing an offset printed matter according to the present invention, the offset printing is performed under a printing pressure smaller than 0.1 mm.

  In addition, in the method for producing an offset printed matter according to the present invention, advantageously, in the offset printing, a plurality of printing layers are integrally laminated on the printing surface of the substrate, while each printing layer For each printing, an intermediate curing process or an intermediate drying process of the printed layer is performed.

  Thus, in the offset printed matter according to the present invention, the printing layer is composed mainly of a pigment mainly composed of particles having a particle diameter of 2 to 9 μm at a ratio of 5 to 35% in terms of the ink solid content weight ratio. Using the contained ink, the light resistance can be remarkably improved by being formed at a thickness of at least 2 μm and being configured such that the total thickness of the printed layer is 4 μm or more. Therefore, the outdoor application of the offset printed matter, which has been regarded as difficult in the past, can be advantageously realized.

  As a result, the offset printed matter is a molded product obtained by press molding into a predetermined shape, and further, a surface in which a resin layer having a predetermined thickness is integrally formed on the back side of such an offset printed matter. As a decorative material, it can be advantageously used for an article or a member arranged outdoors such as a vending machine, or for an interior member or part of an automobile for which a strict light resistance standard is required.

  Further, according to the method for producing an offset printed matter according to the present invention, such an offset printed matter having excellent light resistance is advantageously obtained with good productivity while ensuring a high-quality pattern that is characteristic of the conventional offset printed matter. It has the characteristics that can be.

  By the way, the offset printed matter according to the present invention can be easily obtained by using a conventionally known offset printing machine, for example, an offset sheet-fed printing machine or an offset rotary printing machine. Specifically, FIG. As shown, the printing unit comprising a plate cylinder 2, a rubber blanket cylinder 4 and an impression cylinder 6 has one or more stages, and a sheet-like base is provided between the rubber blanket cylinder 4 and the impression cylinder 6. A printing machine in which a predetermined image (picture) given by the plate cylinder 2 is transferred onto the base material 8 by passing the material 8 is used. In such a printing machine, single-color (single-color) printing is performed by a single-stage printing unit, while multi-color printing (color printing) is performed by a plurality of printing units, or only one side of the substrate 8 is printed. One-sided printing, which is the offset printing, and double-sided printing in which offset printing is performed on both sides thereof are employed depending on the purpose. In such a printing unit, as is well known, a predetermined amount of water is supplied onto the plate cylinder 2 by the dampening roller 10 of the dampening device, and the ink A predetermined ink is supplied onto the plate cylinder 2 from the ink roller 12 of the apparatus.

  Here, the base material 8 to be offset printed is appropriately selected from known materials according to the intended use of the offset printed material. For example, in addition to normal printing paper, synthetic paper, plastic A sheet or a film can be used. Among them, when the obtained offset printed matter is press-molded into a predetermined shape and used as a decorative sheet or a decorative panel, polyester, polyamide, polycarbonate, polyurethane, polystyrene, polypropylene, polyethylene, acrylic resin A plastic sheet or film composed of ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, vinyl chloride resin, or the like is preferably used. The plastic sheet or film is advantageously used as a transparent or translucent sheet, and it is desirable that the at least one offset printing layer is formed on the back side of the sheet. The commercial value of the offset printed matter can be advantageously increased with a high-quality image obtained by offset printing while protecting it. In addition, even if it is the thickness of this base material 8, a suitable thickness can be employ | adopted, For example, in thickness of about 10 micrometers-5 mm, especially in thickness of about 30 micrometers-2 mm, it will be used suitably.

  In the present invention, one or both surfaces of the base material 8 are used as printing surfaces, and at least one printed layer is formed by offset printing to obtain a target offset. In this case, the printed layer has a thickness of at least 2 μm or more using an ink obtained by using pigment particles having a large particle diameter, which is completely different from the ink for conventional offset printing. In addition, a pattern or image having excellent light resistance can be formed by forming the total thickness of at least one printing layer formed on the printing surface of the base material to be 4 μm or more. As a result, it can be formed effectively.

  That is, the characteristic ink used for such offset printing is a pigment mainly composed of particles having a particle diameter of 2 to 9 μm in the ink, in an ink solid content weight ratio of 5 to 35. In particular, a pigment mainly composed of particles having a particle diameter of 3 to 6 μm is advantageously used, and the pigment content is preferably the ink solid content weight ratio. A ratio of 10 to 30% is preferably employed. Here, “mainly composed” means that particles in the prescribed particle size range are present in the ink in a proportion of about 60% by weight or more, preferably 80% by weight or more. Is. In addition, if the particle size of the pigment particles used here is too small or the blending amount is too small, the light resistance of the formed printed layer cannot be sufficiently improved, and a sufficient color tone is obtained. This is because it causes problems that are difficult to reveal, and if the particle size of the pigment particles is too large or the amount of pigment is too large, the printing operation by offset printing becomes difficult, Problems such as difficulty in reproducibility are brought about.

  In addition, as such a pigment, various pigments conventionally known as printing pigments can be appropriately selected and used, and generally used colorless or colored inorganic or organic pigments For example, inorganic pigments such as titanium dioxide, barium sulfate, calcium carbonate, magnetic iron oxide, organic pigments such as azo pigments, lake pigments, phthalocyanine pigments, isoindoline pigments, anthraquinone pigments, quinacridone pigments, and carbon black Etc. can be mentioned. In the present invention, among these pigments, those particularly excellent in light resistance are preferably used.

  In addition, the ink used in the present invention contains the above-described pigment in a predetermined ratio, and has the same blending components as conventional printing inks, for example, vehicles such as resins, solvents, plasticizers, oils, waxes, metal Additives such as soaps, surfactants, gelling agents, stabilizers, anti-skinning agents, and antifoaming agents are added and incorporated into dry inks such as natural drying, hot air drying, and infrared drying. Or a curable ink such as a thermosetting type, an ultraviolet curable type (UV), an electron beam curable type (EB), or a vapor curable type.

  And in the present invention, by using such an ink, by offset printing, one printed layer provided by the one-stage printing unit on the surface to be printed of the predetermined substrate 8 is The total thickness of all the printing layers formed in a thickness of at least 2 μm or more and further comprising at least one of such printing layers is configured to be 4 μm or more, whereby the printing layer Therefore, the light resistance of the light can be drastically improved. In particular, in the present invention, increasing the thickness of each printed layer formed by such offset printing can advantageously contribute to the improvement of the light resistance. It is desirable to form each printing layer at a thickness of 3 μm or more, more desirably 4 μm, and the total thickness of all the printing layers is advantageously 6 μm or more, preferably 8 μm or more. Thus, it is configured.

  In addition, even if the thickness of each printing layer formed by offset printing is thinner than 2 μm using the ink according to the present invention, the total thickness of all the printed layers formed by lamination is thinner than 4 μm. Even if it becomes, it becomes difficult to exhibit sufficient light resistance to printed matter. For this reason, in the case where the printing layer is formed as a single layer on the printing surface of the substrate 8, the configuration is such that the thickness of the printing layer of such a single layer is at least 4 μm or more. Will be.

  By the way, when manufacturing the offset printed matter according to the present invention as described above, at least one of the printing layers having a thickness of 2 μm or more is formed into a predetermined base material using the above-described ink by various known offset printing techniques. 8 is formed so that the total thickness of all the printed layers is 4 μm or more, particularly in the present invention, such a single thickness printed layer, Furthermore, a well-known offset printing method using a lithographic printing plate is preferably employed in that a printing layer having a total thickness is advantageously formed to obtain a precise pattern expression. .

  Further, since the ink used in the present invention has a high viscosity and good sharpness, the offset printing operation is advantageously performed at a printing speed not exceeding 60 m / min, in other words, the rubber blanket cylinder 4 in FIG. It is desirable to carry out at the passing speed of the substrate 8 which is sandwiched and moved by the impression cylinder 6 so that the thick printed layer can be advantageously formed. Although this slower printing speed is advantageous in forming a thicker printed layer, in addition to the decrease in productivity of printed matter, it may be restricted by the capabilities of the printing press itself. Considering these points, the lower limit is appropriately set, but generally the lower limit is about 20 m / min, preferably about 25 m / min.

  Furthermore, when the printing layer having a target thickness is offset printed using the ink according to the present invention, the offset printing is advantageously performed under a printing pressure smaller than 0.1 mm. By adopting such a printing pressure, an offset printing layer having a thick thickness can be effectively formed. In particular, a printing pressure of 0.03 mm to 0.08 mm is suitably employed. It can be done. Here, the printing pressure is determined by the relationship between the gap between the rubber blanket cylinder (4) and the impression cylinder (6) and the thickness of the substrate (8). The value is obtained by subtracting the value of the former gap from the thickness, and in the present invention, offset printing is advantageously performed so that the value is smaller than 0.1 mm.

  In addition, in the present invention, in the case where a plurality of printing layers are integrally laminated on the printing surface of the substrate 8 by offset printing as described above, for each printing of each printing layer, A step of performing an intermediate curing process or an intermediate drying process on the printed layer is advantageously employed. However, the substrate 8 that has passed through the printing unit at the final stage in the offset printing machine is subjected to a predetermined curing process or drying process using the same means as in the past, and the substrate 8 covered with such a substrate 8 is subjected to a predetermined curing process. Although at least one printing layer formed on the printing surface is supposed to be completed as a final solid film, as described above, the printing layer immediately after printing is used in the next printing process. If a certain degree of curing treatment or drying treatment is performed before reaching the thickness, the thickness of the printed layer subjected to such treatment can be advantageously maintained, and the phenomenon of thinning in the subsequent steps can be prevented. This can be effectively avoided, and is a means suitably employed in the present invention.

  And the offset printed matter obtained in this way can be suitably used particularly in outdoor applications where light hits, utilizing its excellent light resistance. Of course, in the case where the substrate is a plastic sheet, it can be used as a surface decorative sheet or the like in the form of a molded product that is press-molded into a desired shape. It will be used after being placed and fixed in

  At that time, the image given by the offset printing layer is expressed by FM screening (Frequency Modulation Screening) using a spot diameter of 10 to 30 μm so that the image or the pattern at the forming corner is not extended. This is preferably adopted. Note that this FM screening is a method that expresses the density of an image not by the size of halftone dots, but by the area of fine dots, as in AM screening, and beautifully reproduces continuous tones at high density. In addition, since the dots are irregularly arranged, moire and the like are not generated, the reproducibility of details is improved, and a highly saturated printing color can be expressed, and thereby, an image of a press-molded offset printed matter The quality can be advantageously increased.

  Here, in order to obtain a molded product of a predetermined shape of the offset printed matter, the press molding method as described above is advantageously employed, but of course, the present invention is not limited to this, and other known molding methods can also be used. It can be adopted as appropriate. For example, the offset printed matter can be formed into a desired shape by employing a technique such as vacuum forming, pressure forming, or drawing.

  Further, the offset printed matter according to the present invention has a predetermined thickness on the back side in the form of a sheet as it is printed or in the form of a molded product that has been press-molded as described above to give a predetermined shape. By integrally forming a resin layer, surface decorative materials such as display panels and decorative panels for vending machines, display panels and decorative panels for automobile interior parts, and display panels and decorative panels for home appliances As a result, it is preferably used. Such a surface decorative material is obtained by so-called insert molding in which a resin injection molding operation similar to the conventional one is performed in a state in which an offset printed material is set in a molding cavity of a predetermined molding die. It can be easily obtained as a product in which an offset print is integrally fixed on the surface of a resin molded product.

  As described above, the offset printed product according to the present invention is obtained as having excellent light resistance under the high productivity inherent in offset printing. It can be advantageously used with high economic efficiency as a field that has been regarded as difficult, particularly as a product for outdoor use or a product that requires high light resistance in automobiles and the like.

  Hereinafter, representative examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited by the description of such examples. It goes without saying. In addition to the following examples, the present invention includes various changes and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention, in addition to the above specific description. It should be understood that improvements can be made.

  First, using a normal plate making equipment used for offset printing, a printing plate subjected to FM screening using a spot diameter of 20 μm was prepared from a predetermined pattern sample.

  Also, four color inks comprising cyan (C), magenta (M), yellow (Y) and black (K) used for offset printing were prepared. That is, as the ink for cyan (C), a phthalocyanine pigment mainly composed of particles of 3 to 6 μm is contained in a proportion of 20 to 22% in an ink solid content weight ratio, and is ultraviolet curable according to a conventional method. The ink for magenta (M) prepared as an ink uses a quinacridone pigment mainly composed of particles of 3 to 6 μm, so that it is contained at a ratio of 23 to 27% by weight ratio of ink solids. Further, the yellow (Y) ink uses an insoluble azo pigment mainly composed of 3 to 6 μm particles so that it is contained at a ratio of 23 to 27% in terms of the ink solid content weight ratio. Further, the black (K) ink uses a carbon black pigment mainly composed of 3 to 6 μm particles, and it is contained in a ratio of 20 to 23% in terms of ink solids weight ratio. , Respectively, it was prepared as an ultraviolet curable ink as in the prior art construction. The particle size of the pigment particles in each ink was measured by Shimadzu Corporation particle size measuring instrument in a state where the specimen was diluted with a solvent and then stirred for 2 minutes with an ultrasonic cleaner to sufficiently disperse the pigment: It measured using SALD-200V ER.

  Next, the prepared printing plate is set on a commercially available offset printing machine having a structure in which four stages of printing units as shown in FIG. 1 are arranged, while the four kinds of ultraviolet curable inks prepared above are used. Were thoroughly stirred and put into each printing unit. Then, the ink roller of the offset printing machine was rotated, and each ink was uniformly supplied in the roller axial direction while kneading each ink so that each ink was supplied uniformly.

  Further, while setting the printing pressure in the offset printing press to 0.05 mm, the rotational speeds of the rubber blanket cylinder 4 and the impression cylinder 6 in each printing unit are adjusted so that the printing speed is about 56 m / min. Then, the light amount of the ultraviolet lamp arranged on the exit side of the final-stage printing unit was adjusted so that the amount of ultraviolet light necessary for ink curing could be applied to the printed matter sent from the final-stage printing unit.

  Then, a 0.2 mm thick polycarbonate sheet is sequentially passed through the offset printing machine adjusted as described above, and the full color printing is performed continuously to obtain a target color tone. An offset print was obtained.

  With respect to the offset printed matter thus obtained, the total thickness of the entire printed layer was measured with a measuring machine manufactured by Mitutoyo: ID-C112C and found to be about 5 to 8 μm. In addition, the target thickness of the printing layer printed in each printing unit was 2 to 4 μm in the evaluation of the monochromatic solid printing portion.

  Further, the offset printed matter thus obtained was subjected to a light resistance test for 600 hours using a light resistance tester: FAL-3 manufactured by Suga Test Instruments Co., Ltd. at Aichi Industrial Technology Center. Compared to offset printed matter (printed layer thickness: about 1 μm), it showed extremely excellent light resistance, and was confirmed to be sufficiently practical for outdoor use.

It is principal part explanatory drawing which shows an example of the printing unit in an offset printing machine.

Explanation of symbols

2 Plate cylinder 4 Rubber blanket cylinder 6 Impression cylinder 8 Base material 10 Dampening roller 12 Ink roller

Claims (12)

In an offset printed matter in which at least one printed layer is formed by offset printing on the printing surface of the substrate,
The printed layer is formed in a thickness of at least 2 μm or more using an ink containing a pigment mainly composed of particles having a particle diameter of 2 to 9 μm at a ratio of 5 to 35% by weight of the ink solid content. And an offset printed matter excellent in light resistance, wherein the total thickness of at least one or more printed layers formed on the printing surface is 4 μm or more.   The offset printed matter with excellent light resistance according to claim 1, wherein the offset printing is performed using a lithographic printing plate.   The offset printed matter with excellent light resistance according to claim 1, wherein the base material is a plastic sheet.   The light resistance according to claim 3, wherein the plastic sheet is a transparent or translucent sheet, and the at least one printed layer is formed on the back side of the transparent or translucent sheet. Excellent offset printed matter.   The offset printed matter with excellent light resistance according to claim 3 or 4, wherein the offset-printed plastic sheet is press-molded into a desired shape.   The offset printed matter with excellent light resistance according to claim 5, wherein the image provided by the printed layer is expressed by FM screening using a spot diameter of 10 to 30 μm.   A surface decorative material using the offset printed matter according to any one of claims 1 to 6, wherein a resin layer having a predetermined thickness is integrally formed on the back side thereof. In a method for producing an offset printed matter in which at least one printing layer is formed on a printing surface of a substrate,
A thickness of at least 2 μm or more by offset printing using an ink containing a pigment mainly composed of particles having a particle size of 2 to 9 μm at a ratio of 5 to 35% by weight of the ink solid content. And forming in
An offset printed matter having excellent light resistance, wherein the offset printing operation is performed so that the total thickness of at least one or more printed layers formed on the printing surface is 4 μm or more. Manufacturing method.   The method for producing an offset printed matter having excellent light resistance according to claim 8, wherein the offset printing is performed using a lithographic printing plate.   The method for producing an offset printed matter with excellent light resistance according to claim 8 or 9, wherein the offset printing is performed at a printing speed not exceeding 60 m / min.   The method for producing an offset printed matter with excellent light resistance according to any one of claims 8 to 10, wherein the offset printing is performed under a printing pressure smaller than 0.1 mm. In the offset printing, a plurality of printing layers are integrally laminated on the surface to be printed of the base material, and an intermediate curing process or intermediate drying of the printed printing layer is performed for each printing layer printing. The method for producing an offset printed matter excellent in light resistance according to any one of claims 8 to 11, wherein the treatment is performed.

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