JP2012035437A - Method for manufacturing ultraviolet-curable type printed matter and ultraviolet-curable type printed matter using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing ultraviolet-curable type printed matter, which includes a step to form an image in ultraviolet-curable type black ink which shows excellent surface hardness and also, superior adhesion with a paper base material, as well as ultraviolet-curable type printed matter which is available by the manufacturing method.SOLUTION: This method comprises a step (step 1) to form an image of ultraviolet-curable type composition on the base material, using offset printing technique, a step (step 2) to irradiate with ultraviolet light with the help of a light emitting diode (LED) and a step (step 3) to irradiate with ultraviolet light with the help of an ultraviolet lamp in that order. In addition, the method is characteristic in that the step (step 1) which uses paper as a base material and forms an image in the ultraviolet-curable type composition, adopts a function-discrete irradiation system inclusive of a step to form an image in the ultraviolet-curable type black ink.

Description

  The present invention relates to a method for producing an ultraviolet curable print using a light emitting diode (LED) and an ultraviolet lamp in combination as an ultraviolet light source, and an ultraviolet curable print using the method.

  In the production of ultraviolet curable prints, UV lamps such as low pressure, high pressure mercury lamps, xenon lamps, metal halide lamps have been widely used as curing systems as light sources.

  In recent years, an ultraviolet device using a light emitting diode (LED) as a light source has been developed as a curing system that replaces these ultraviolet lamps (see, for example, Patent Document 1), and in the printing field such as an ink jet system, manufacture of printed matter corresponding to the LED light source. Methods and ink compositions used therefor have been studied (see, for example, Patent Document 2 and Patent Document 3). Since the UV-LED light source has a longer light source life than the existing ultraviolet lamp system and is greatly superior in energy saving, commercialization of the UV-LED light source is strongly demanded by companies in the printing industry.

  On the other hand, the disadvantage of the UV-LED light source is that the film drying property (curability) of the ultraviolet curable composition is greatly inferior to that of the ultraviolet lamp light source. Due to the large loss of ultraviolet energy, it is difficult to obtain good film strength, which hinders the spread of this method. The UV-LED light source has an emission peak wavelength of about 200 nm in a special application, but the emission intensity is extremely weak. A general-purpose UV-LED light source having an emission intensity applicable for printed curing uses an emission wavelength range of 365 to 365 nm. It is limited to 420 nm. Therefore, the total amount of ultraviolet energy is small compared to an ultraviolet lamp light source that emits ultraviolet light of a wide wavelength, and the amount of radicals generated from the photopolymerization initiator is small, so that the polymerization reaction is susceptible to oxygen inhibition. Can be mentioned. In addition, since the amount of ultraviolet energy in the relatively short wavelength region is relatively short, it has been confirmed that UV compositions obtained by LED irradiation generally tend to have inferior curability on the coating surface.

  On the other hand, the ultraviolet drying method using an ultraviolet lamp light source has excellent curability but tends to have poor substrate adhesion to a printing substrate due to the effect of film shrinkage during curing. Especially for UV curable black ink, the UV energy applied to the printed film attenuates sharply from the upper layer to the lower layer, resulting in a difference in volume shrinkage during the curing reaction between the upper and lower layers. There was a problem that adhesion failure due to shrinkage strain was likely to occur.

  Although there is an example in which a UV-LED light source is irradiated to an ultraviolet curable composition, it is very wide and cannot be said to have sufficient specificity and practicality (for example, see Patent Document 4).

  In addition, in order to prevent curing inhibition due to oxygen inhibition, a method of combining a UV-LED and a mercury UV lamp as a light source is known (for example, see Non-Patent Document 1). For example, by combining a mercury lamp that mainly emits ultraviolet rays in a low wavelength region, it is possible to improve the curing reaction particularly on the film surface of the ultraviolet curable composition.

  However, this mercury UV lamp combining method has been proposed as a means for improving the curability of coating varnish in building materials and the like, as shown in Non-Patent Document 1, and what is a printing application for forming an image? The fields are different.

JP 2005-153193 A JP 2006-176734 A JP 2006-206875 A Special table 2006-511684 RADTECH REPORT MARCH / APRIL 2008 "UV-LED Curing It's Beginning to Look a Lot Like Christmas"

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing an ultraviolet curable printed matter having a step of forming an image of an ultraviolet curable ink having excellent surface hardness and excellent adhesion to a paper-based substrate, and the production method It is providing the ultraviolet curable printed matter obtained by this.

  The inventors first formed an image of UV curable black ink by offset printing on the base paper, and then secured the adhesion to the paper by UV-LED irradiation as the first UV light source. And it discovered that the said subject could be achieved by employ | adopting the irradiation system of function separation which obtains the hardness of a coating film by the ultraviolet lamp irradiation as a 2nd ultraviolet light source, and came to this invention.

  In the present invention, a step of forming an image of an ultraviolet curable composition by offset printing on a substrate (step 1), a step of irradiating ultraviolet rays with a light emitting diode (LED) (step 2), and irradiating ultraviolet rays with an ultraviolet lamp. A method for producing an ultraviolet curable print having steps (step 3) in this order, wherein the substrate is paper, and the step of forming an image of the ultraviolet curable composition (step 1) is performed using ultraviolet curable black ink. Provided is a method for producing an ultraviolet curable printed material, which comprises a step of forming an image.

  That is, in the present invention, firstly, a step (step 1) of forming an image formed by a dot and / or a line drawing with ultraviolet curable black ink by offset printing on a paper as a base material, a light emitting diode ( There is provided a method for producing an ultraviolet curable printed matter, comprising a step of irradiating ultraviolet rays with an LED (step 2) and a step of irradiating ultraviolet rays with an ultraviolet lamp (step 3) in this order.

  Secondly, the present invention provides a printed matter obtained by the above-described method for producing an ultraviolet curable printed matter.

  According to the present invention, a layer of an ultraviolet curable composition is formed on the surface of a paper, and by first using a UV-LED as an ultraviolet light source, adhesion to the paper can be secured, and then a second ultraviolet light source And UV lamp irradiation can provide a coating with sufficient hardness. By adopting the present invention, even in the case of UV curable black ink that has a large UV energy loss of carbon, by using both UV-LED and UV lamp as the UV irradiation light source, it is possible to obtain a printed matter with excellent curing and adhesion. I can do it.

  The production method of the present invention includes a step of forming an image with ultraviolet curable ink, which is an ultraviolet curable composition, by offset printing on paper (step 1), and a step of irradiating ultraviolet rays with a light emitting diode (LED) (step 2). And a step of irradiating ultraviolet rays with an ultraviolet lamp (step 3) in this order.

That is, in the method for producing an ultraviolet curable printed matter of the present invention, first, an image formed by dots and / or a line drawing by ultraviolet curable black ink or the like is formed on a sheet by offset printing, and an emission peak wavelength 350 The process of irradiating ultraviolet rays with a light emitting diode (LED) having an ultraviolet light intensity of 5 to 50 mJ / cm ² and an irradiation intensity of 500 mW / cm ² or more, and A step of irradiating ultraviolet rays in a range of 100 mJ / cm ² .
The present invention is not limited to this example.

  The printing ink used for the production of the printed matter of the present invention is effective not only for ultraviolet curable ink, but also for multiple overlaps with process color ink, special ink, etc. It is valid.

  FIG. 1 shows the overall configuration of the present invention. The printing paper 1 is supplied to the printing unit 2 from the feeder unit. The printing unit 2 includes a plurality of printing units. For example, if normal process color printing is used, black UV ink, indigo UV ink, red UV ink, and yellow UV ink are used, so four units are required. In addition, if the configuration is such that a special color UV ink for adding the number of colors is added, or if a configuration in which UVOP varnish is overlapped, the number of printing units corresponding to this is required. Typically, the total number of printing units is about 1-10.

  The printing paper 1 printed by the printing unit 2 is irradiated with ultraviolet rays when passing through the lower part of the installed UV-LED irradiator 3, and also when passing through the lower part of the installed ultraviolet UV lamp 4. The printed UV ink layer is cured by receiving ultraviolet rays.

  FIG. 2 shows a printing configuration diagram when the coating machine 5 is added to the printing unit 2 and a UV coating varnish layer is formed on the upper surface of the UV ink layer. The printing method described in the present invention can also be applied to this printing configuration. Of course, the effect can be obtained. The coating machine 5 includes a chamber 6, an anilox roll 7, a blanket cylinder 8 and an impression cylinder 9. The UV coating varnish is accommodated in the chamber 6 and applied to the upper surface of the UV ink layer on the printing paper 1 through the anilox roll 7 and the blanket cylinder 8 to form a UV coating varnish layer. Even when the UV coating varnish is applied not by the chamber method but by the roll method, the printing method described in the present invention can be similarly applied and the effect can be obtained. In the roll method, it is possible to control the amount of varnish supplied by adjusting the roll interval between the varnish passing rolls. However, in the point that the varnish supply amount does not fluctuate due to various printing conditions such as temperature, varnish supply It is particularly desirable to employ a chamber system that excels in keeping the amount more uniform.

  The printing paper used in the printed matter of the present invention is not particularly limited. For example, coated paper such as high-quality paper, coated paper, art paper, imitation paper, thin paper, thick paper, matte coated paper, mirror coated paper, or the like is used. The effects of the present invention can be obtained for various papers such as special papers such as inkjet papers, sublimation heat transfer papers, and non-carbon papers in addition to working papers and non-coated papers.

  The printing ink used for the production of the printed matter of the present invention is not particularly limited as long as it is a composition that cures against ultraviolet rays emitted from ultraviolet light emitting diodes or ultraviolet lamps, and publicly known UV-LED inks and UV inks are used. For example, depending on the printing method, offset, waterless, gravure, flexo, silk screen, ink jet, and other UV curable inks conventionally used for printing can be adopted. .

  There are no particular limitations on the densitometers (spectral densitometer, spectrophotometer, optical densitometer, reflection densitometer) used for density value management when producing printed matter described in the present invention, and publicly known and publicly used used in the printing field For example, products such as X-Rite (GretagMacbeth), FAG Graphic Systems, TECHKON, and Ihara Electronics Co., Ltd. can be used.

  As the ultraviolet curable black ink that can be used in the present invention, a publicly known and publicly available ultraviolet curable black ink can be used. For example, the Dicure Ink Series (manufactured by DIC Graphics) can be used.

  As the emission wavelength of ultraviolet rays emitted from the ultraviolet light emitting diode light source used for producing the printed material of the present invention, for example, those having an emission peak wavelength of about 350 to 420 nm are preferable.

Regarding the cumulative amount of light (mJ / cm ² ) of ultraviolet rays irradiated to the ultraviolet curable composition from the ultraviolet light emitting diode light source used for producing the printed matter of the present invention, the type of ultraviolet curable black ink on the printing paper However, since it varies depending on the thickness of the printing layer and the like, it cannot be strictly specified, and preferable conditions are appropriately selected. For example, the integrated light amount value is about 3 to 100 mJ / cm ² , and more preferably 5 to 5 m. It is about 200 mJ / cm ² .

With respect to the irradiation intensity (mW / cm ² ) of the ultraviolet ray irradiated to the ultraviolet curable composition on the printing paper from the ultraviolet light emitting diode light source used for producing the printed matter of the present invention, the ultraviolet light emitting diode light source arranged in the printing direction. The appropriate irradiation intensity range fluctuates depending on various conditions such as the number of light sources, the irradiation distance from the light source to the composition, and the like, but it cannot be strictly specified, and preferable conditions are appropriately selected. For example, 500 mW / cm It is preferable that it is ² or more.

  As the ultraviolet lamp light source used for producing the printed matter of the present invention, a publicly known one can be used, and examples thereof include a metal halide lamp, a mercury lamp, a xenon lamp, and an excimer lamp.

Regarding the integrated light amount of ultraviolet rays irradiated to the ultraviolet curable composition from the ultraviolet lamp light source used for producing the printed material of the present invention, it depends on the type of the ultraviolet curable composition on the printing paper, the thickness of the printing layer, etc. Since it is different, it cannot be specified strictly, and preferable conditions are appropriately selected. For example, the integrated light amount value is about 5 to 200 mJ / cm ² , and more preferably about 10 to 100 mJ / cm ^2. .

  Good film curability cannot be obtained under conditions where the integrated light quantity value is significantly below the above range, while conditions where the integrated light amount value is significantly above the above range are not preferable from the viewpoint of energy saving.

  Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Method for producing printed matter [Example 1]
Printed materials were produced under the ink conditions shown in Table 1, UV-LED irradiation conditions, and ultraviolet lamp irradiation conditions. Using 0.150 ml of Dicure Abilio SE EP process black ink (DIC Graphics) as UV ink, using a simple color developer (RI tester, Toyosei Seiko), OK Special Art Post + (quantitative 186 g) / M ² , made by Oji Paper Co., Ltd.) and printed in an area range of about 220 cm ² . Using an ultraviolet light emitting diode irradiation device (Panasonic Electric Works, ANUD8002T01) having an emission wavelength peak of 385 nm as an ultraviolet light emitting diode light source, directly below the ultraviolet light emitting diode light source with respect to OK special art post + printed with UV ink The irradiation distance is 1 cm, the output is 100%, one lamp, the line speed is 120 m / min. UV irradiation was performed. When the integrated light quantity value and irradiation intensity irradiated on the printed matter from the UV-LED light source were measured using UNIMETER UIT-150-A (made by USHIO INC.), 22 mJ / cm ² and 999.9 mW / cm ² or more (measurement) It was a numerical value exceeding the detection limit of the instrument). Subsequently, a metal halide lamp (made by Eye Graphics Co., Ltd.) is used as the ultraviolet lamp light source, and the printed distance is 11 cm, the output is 120 W / cm, one lamp, and the line speed is 120 m so as to pass through the ultraviolet lamp light source. / Min. UV irradiation was performed. The integrated light amount irradiated onto the printed material from the ultraviolet lamp light source was measured using UNIMETER UIT-150-A (made by USHIO INC.) And found to be 23 mJ / cm ² . The black density of this printed matter was measured with a FAG VIPENDENS 400P optical densitometer manufactured by FAG Graphic Systems. The black density value was 2.6.

[Examples 2 to 4]
Printed materials were produced under the ink conditions shown in Table 1, UV-LED irradiation conditions, and ultraviolet lamp irradiation conditions. The ink was printed on the OK special art post + in the same manner as in Example 1 and then irradiated with ultraviolet rays. As the UV ink, Dicure Abilio SE EP Process Black ink (manufactured by DIC Graphics) was used. For Example 2, the ink deposit amount was 0.150 ml and the black density was 2.6 as in Example 1, and for Examples 3 and 4, the ink deposit amount was 0.175 ml and the black density was 2.8. It was adjusted. In Examples 2 and 4, for UV-LED irradiation, the irradiation distance was 1 cm, the output was 50%, one lamp, and the line speed was 120 m / min. The integrated light quantity value and the irradiation intensity were measured by the same method as in Example 1, and the result was 12 mJ / cm ² and 809 mW / cm ² . In Example 3, UV-LED ultraviolet irradiation of 22 mJ / cm ² and 999.9 mW / cm ² or more (numerical values exceeding the detection limit of the measuring device) under the same conditions as in Example 1 was performed. About Examples 2-4, the ultraviolet lamp ultraviolet irradiation (23 mJ / cm < ² >) which is the irradiation conditions similar to Example 1 was implemented following UV-LED ultraviolet irradiation.

[Comparative Examples 1-4]
Printed materials were produced under the ink conditions shown in Table 2, UV-LED irradiation conditions, and ultraviolet lamp irradiation conditions. The ink was printed on the OK special art post + in the same manner as in Example 1 and then irradiated with ultraviolet rays. As the UV ink, Dicure Abilio SE EP Process Black ink (manufactured by DIC Graphics) was used. For Comparative Examples 1 and 2, the ink volume was 0.150 ml and the black density was 2.6, and for Comparative Examples 3 and 4, the ink volume was adjusted to 0.175 ml and the black density was 2.8. In Comparative Examples 1 and 3, only the ultraviolet lamp irradiation was performed, the irradiation distance was 11 cm, the output was 120 W / cm, two lamps, and the line speed was 120 m / min. When the integrated light amount value was measured by the same method as in Example 1, it was 46 mJ / cm ² . In Comparative Examples 2 and 4, only UV-LED irradiation was performed, the irradiation distance was 1 cm, the output was 100%, two lights, and the line speed was 120 m / min. When the integrated light amount value and the irradiation intensity were measured by the same method as in Example 1, the values were 44 mJ / cm ² and 999.9 mW / cm ² or more (numerical values exceeding the detection limit of the measuring device). .

[Evaluation method for printed matter]
As a method for evaluating the drying property (curability) of the printed matter after irradiation with ultraviolet rays, the dried state of the ink was confirmed by a nail scratch test and evaluated in the following five stages.
5 ... Completely dry, no scratches on the film even when rubbed with strong force 4 ... Almost dry, slightly rubbed on the film when rubbed with strong force 3 ... The film is almost dry, and the film is clearly scratched when rubbed with a strong force. 2 ... It is slightly dry, and the film is clearly scratched even with a weak force.

As a method for evaluating the adhesiveness of printed matter after irradiation with ultraviolet rays, it was confirmed by a tape peeling test. The cellophane pressure-sensitive adhesive tape was strongly pressed against the ink film after being irradiated with ultraviolet rays, and quickly pulled up in the vertical direction and peeled off to evaluate the adhesion state of the ink film on the paper in the following five stages.
5: Completely bonded, almost all area remains without peeling 4: Almost bonded, more than half area remains without peeling 3: Almost bonded About half of the area remains without peeling 2 ... Slightly adhered, more than half of the area peels 1 ... Not adhered at all, almost all the area peels When the cellophane adhesive tape was peeled off, when the paper surface was broken and the ink film was peeled off with the paper, it was determined that the ink film was completely adhered on the paper (step: 5).

The numerical values in Tables 1 and 2 are integrated light quantity values, and the unit is (mJ / cm ² ).

  In the results of Examples 1 to 4, it was confirmed that both UV-LED irradiation and ultraviolet lamp irradiation were used in a state where there was no practical problem (3 or more) in terms of drying and adhesion.

  In the results of Comparative Examples 1 to 4, it was confirmed that under conditions of only UV-LED irradiation or only ultraviolet lamp irradiation, the drying property or adhesiveness was in a state (2 or less).

  The method for producing an ultraviolet curable print of the present invention and the ultraviolet curable print using the same can be suitably used in graphic image printing, printed graphics, plastic electronic materials, and the like that require printing by ultraviolet curing.

It is process drawing explaining the process of printing the ultraviolet curable printed material which is this invention with UV ink or UVOP varnish. It is process drawing explaining the process of printing the ultraviolet curable printed material which is this invention with UV ink or UVOP varnish, and also applying UV coating varnish with a coating machine.

1 ... Printing paper 2 ... Printing machine (printing UV ink, UVOP varnish)
3 ... UV LED irradiation device 4 ... UV lamp irradiation device 5 ... Coating machine (applying UV coating varnish)
6 ... Chamber 7 ... Anilox roll 8 ... Blanket cylinder 9 ... Impression cylinder

Claims (7)

A step of forming an image of an ultraviolet curable composition by offset printing on a substrate (step 1), a step of irradiating ultraviolet rays with a light emitting diode (LED) (step 2), and a step of irradiating ultraviolet rays with an ultraviolet lamp (step 3). ) In this order, wherein the base material is paper, and the step of forming an image of the ultraviolet curable composition (step 1) forms an image of the ultraviolet curable ink. The manufacturing method of the ultraviolet curable printed matter characterized by having a process. 2. The process according to claim 1, wherein the step of forming an image of the ultraviolet curable composition (step 1) includes a step of forming an image of the ultraviolet curable black ink and a multicolor overprinting step depending on the ultraviolet curable ink. A method for producing an ultraviolet curable printed material. The method for producing an ultraviolet curable printed material according to claim 1, wherein the light emitting diode (LED) is a light emitting diode (LED) having an emission peak wavelength of 350 to 420 nm. The ultraviolet integrated light quantity by said light emitting diode (LED) exists in the range of 3-100 mJ / cm < ² >, and the ultraviolet integrated light quantity by an ultraviolet lamp exists in the range of 5-200 mJ / cm < ² >. Manufacturing method of ultraviolet curable printed matter. The method for producing an ultraviolet curable printed material according to any one of claims 1 to 4, wherein the irradiation intensity of the light emitting diode (LED) is 500 mW / cm ² or more. An ultraviolet curable printed matter obtained by the method for producing an ultraviolet curable printed matter according to any one of claims 1 to 5. The above-mentioned ultraviolet curable print has a black density value measured by a spectrophotometer in an ultraviolet curable black ink image or a multicolor overprint image containing ultraviolet curable black ink in a range of 2.2 to 2.9. The ultraviolet curable printed material according to claim 6.

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