JP5408838B2 - Display board - Google Patents

Description

  The present invention relates to a display panel printed using an ultraviolet curable inkjet ink.

Conventionally, for example, in electric signboards, home appliances, measuring instruments, etc., various characters etc. are screen-printed with solvent-type ink or ultraviolet curable ink on the display board, and LEDs etc. on the back to improve visibility even at night A light-emitting device having a light-emitting body installed therein has been put into practical use.
Such display boards have a variety of designs, and are generally multi-layered (generally 3 to 10 layers) full-surface printing or partial printing to satisfy functionality and design, and then a vacuum molding machine or a pneumatic molding machine. Forming processing is carried out in order to create a three-dimensional three-dimensional display board.
In addition, a generally sealed box with the display surface side closed with a transparent resin plate such as a transparent acrylic plate in order to reduce the speed at which the visibility of the display plate deteriorates due to dirt such as high temperature and humidity, sunlight ultraviolet rays, and dust. It is composed of a body and assembled at a predetermined location.

  However, in the creation of the display board by the screen printing method, in order to print 3 to 10 layers as described above, the printing plate corresponding to each printing layer is created and each printing layer is printed each time. This process is essential and requires a great deal of labor, cost, and time.

  Therefore, multicolor design printing can be done in one process. It has been desired to produce such a display plate by an ink jet printing method using an ultraviolet curable ink jet ink which has a high curing speed and is capable of easily obtaining a tough printed film.

  Since UV curable inkjet inks used in such inkjet systems are required to have low viscosity, monofunctional radically polymerizable monomers are used as indispensable components as photopolymerization reactive compositions. doing.

  However, the monofunctional radically polymerizable monomer alone has a low curing rate and low crosslinking density, so it is inferior in formability such as forming, and PC (polycarbonate), which is generally used as a substrate for printing and molding display panels. It is considered that the adhesiveness to a PET (polyester) sheet is insufficient. Furthermore, due to the presence of the unreacted monofunctional radical polymerizable monomer, tack may remain on the printed film, impairing mass-production printing workability, and peeling of the printed film or deterioration such as swelling may occur in a high temperature and high humidity environment. Thus, the basic problem of impairing the visibility of the display board is included.

  In order to remedy such defects, it is usual to mix a polyfunctional radical polymerizable oligomer with a monofunctional radical polymerizable monomer. However, when such a compounding is performed, the above defects are sufficiently improved. You can't do it.

  In Patent Document 1, by adopting a configuration in which a polyfunctional radical polymerizable monomer is a main component of a photopolymerization reactive composition and any one of α, β-unsaturated ether monomers is employed, moldability ( Trying to improve toughness) and adhesion.

However, in the above configuration, since the crosslinking density is excessively high and the flexibility is insufficient to be deformable due to rapid curing, it is different from the case where the main component is a conventional monofunctional radical polymerizable monomer. There were inconveniences in molding due to the purpose.
In Patent Document 2, in order to improve the inconvenience in Patent Document 1, a monofunctional radical polymerizable monomer is used as a main component of the photopolymerization reactive composition, and at least one kind of α, β-unsaturated ether monomer is used. The composition which is an indispensable ingredient is adopted.
Certainly, in the case of the above configuration, the flexibility for improving the deformability is improved as compared with the case of the configuration according to Patent Document 1, but the adhesiveness is not always sufficient, and UV curing is performed. Also, it is not always sufficient to reduce the tackiness on the ink surface after that, that is, to reduce the stickiness.

Furthermore, in display panels that use UV-curable ink-jet ink, the display panel visibility is prevented by preventing the peeling of printed films and the occurrence of blistering due to adhesive deterioration when the display panel is used in a hot and humid environment. There is no known technique relating to ensuring sufficient.
JP-T-2004-526820 JP 2005-532445 A

  As is clear from the background art, in the ultraviolet curable ink-jet ink, a monofunctional radical polymerizable monomer is employed as a main component, but the selection and further combination thereof have not been sufficiently studied. Therefore, good moldability rich in flexibility, adhesion to the substrate, tackiness on the substrate, and further on the substrate in a high temperature and high humidity (for example, 60 ° C., 95 to 99% humidity) environment. No improvement has been achieved with respect to peeling or blistering (hereinafter referred to as high temperature and high humidity deterioration).

  In view of such a situation, in the present invention, as a photopolymerization reactive composition, based on a specific monofunctional radical polymerizable monomer, if necessary, another monofunctional radical polymerizable monomer, UV curable inkjet ink obtained by combining with polyfunctional radically polymerizable oligomer is used to form a printed film on a display board such as an automobile meter. An object of the present invention is to provide a display board such as a measuring instrument meter that is satisfactory in all elements.

To solve the above problems, the basic configuration of the present invention, a transparent PMMA resin plate on the front, a Viewing plate to be placed under substantially sealed environment arranging the light emitter to at least a portion of the back, the display plate In a display board that has been printed with a UV curable inkjet ink on a translucent resin substrate and has been cured with a predetermined UV,
The ultraviolet curable ink-jet ink has a photoreaction initiator and a photopolymerization reactive composition as essential components, and the photopolymerization reactive composition contains a polyfunctional radical polymerizable oligomer, and then phenoxyethyl acrylate and , one monomer and its remaining of a monofunctional radically polymerizable monomer aromatic monofunctional radically polymerizable monomer, the aliphatic monofunctional radical polymerization monomer and alicyclic of cycloaliphatic monofunctional radical polymerization monomer either of formula monofunctional radical polymerization monomer (however, phenoxyethyl excluded phenoxyethyl acrylate, and the cycloaliphatic monofunctional radical polymerization monomer formulated with phenoxy ethyl acrylate) by a one monomer selected from among a combination according to total 3 kinds of monomers, polyfunctional radically polymerizable oligomer And a phenoxyethyl acrylate, cycloaliphatic monofunctional radical polymerization monomer, the weight ratio of the remaining of the monofunctional radically polymerizable monomer, respectively 0.05 to 0.4: 1: 0.1 to 0.7 : It consists of the display board based on forming a printing film with the ultraviolet curable inkjet ink based on being in the range of 0.1-0.7.

  In the present invention based on the above basic configuration, the moldability, adhesiveness, and tackiness are good, and it is possible to prevent the occurrence of high-temperature and high-humidity deterioration, and promptly produce a display panel with high design and high visibility. It becomes possible.

As is apparent from the basic configuration, the display panel of the present invention is based on the premise that the ultraviolet curable ink-jet ink is printed on the light-transmitting resin substrate and is then cured. photopolymerization composition of the ink, not only the polyfunctional radically polymerizable oligomer, a monofunctional radically polymerizable monomer include phenoxyethyl acrylate + alicyclic one of the monofunctional radically polymerizable monomer + the remaining of Aromatic monofunctional radical polymerizable monomer which is a monofunctional radical polymerizable monomer + aliphatic monofunctional radical polymerizable monomer and alicyclic monofunctional radical polymerizable monomer (however, phenoxyethyl acrylate and phenoxyethyl acrylate) It said excluding alicyclic monofunctional radically polymerizable monomer) formulated with It is basically characterized in that by incorporating a combination of a total of three types of monomers according to one monomer selected from.

  Hereinafter, it will be clarified through experiments that the basic configuration is excellent as an embodiment.

First, showing black ink BL1～BL 3 shown in Table 1, yellow ink Y1～Y 3 shown in Table 2, magenta ink M1 to M 3 shown in Table 3, Table 4 C1～C 3 were prepared cyan ink (the mixing unit by numerical values the following tables are weight%, the ink 1 of each color, while they meet the numerical requirement for the basic configuration, the colored inks 2 3 does not satisfy the numerical requirements.)

The ultraviolet curable ink-jet ink according to Table 1 to Table 4 was repeatedly printed on one side of a polycarbonate resin sheet having a thickness of 0.5 mm (film thickness of 10 μm by one printing), and 400 mJ for one curing using a metal halide lamp. A printed sheet having a thickness of 10 μm to 50 μm that is in close contact with the resin sheet and provided with the ink layer was obtained by performing UV irradiation at a rate of / cm ² .

  About the ink shown in the said Table 1-Table 4 which formed the said printing sheet, about the moldability of the printing sheet in which the coating film which printed and hardened was laminated | stacked, adhesiveness, tackiness, and high temperature and humidity deterioration property was based on the following references | standards. A test was conducted.

Molding test: Molding test: After performing vacuum molding under conditions of 180 ° C. for 30 seconds using a disc having a diameter of 2.5 cm and a width of 1 cm, the cracking state of the coating film was evaluated.
○ Shows no cracks in the paint film.
△ At least part of fine cracks that can be barely confirmed by the naked eye
The state that is occurring automatically.
× Indicates that the entire printed matter is cracked.

Adhesion test: Using a cutter knife, provide a total of 25 squares with a width of 1 mm on the coating film and 5 in the vertical direction and 5 in the horizontal direction, and paste the cellophane tape on the squares to make an angle of 90 °. The degree of the squares that were peeled off at the stage of peeling was evaluated.
○ Indicates a state where the coating film does not peel off.
△ Basically, peeling of the coating film does not occur, but it shows a state in which peeling occurs slightly around the square.
X A state where peeling of the coating film is noticeable is shown.

Tack test: The coating film was contacted with a finger and the sticky feeling was evaluated.
○ Shows no stickiness due to finger touch.
△ Indicates that the touch is slightly sticky, but no trace of touch is left.
X A state in which a trace remains when touched with a finger without completing the cured state.

High-temperature and high-humidity deterioration test: After the printed sheet molded product prepared in the previous molding test is put into a wet test machine at 60 ° C and 99% humidity for 48 hours, the printed sheet molded product is visually checked for peeling and blistering. It was evaluated with.
○ It means that there is no peeling or swelling.
[Delta] indicates a part in which a minute bulge that can be confirmed with a 50x magnifier is partially generated.
× It refers to a state in which peeling or blistering that can be visually confirmed occurs.

  The results of the degree of formability, adhesiveness, tackiness, and high temperature and high humidity deterioration properties according to the above criteria are as shown in Tables 1 to 4 above.

As is clear from the experimental results, in the display panel according to the embodiment of each color ink 1 satisfying the basic configuration, good results can be obtained for the respective characteristics.

On the other hand, in the case of the color inks 2 and 3 that do not satisfy the numerical requirements of the basic configuration, good results cannot always be obtained in the characteristics.

  In the present invention, a transparent or translucent acrylic in which a transparent acrylic cover is arranged in the display direction and an electronic circuit including an LED is arranged in the back direction, and further, the display on the display board is visible. The embodiment by displaying by the cover can be suitably adopted.

Among the ultraviolet curable inkjet ink described in Experiment colors 1, the clock display plate printed material were prepared using the color 1, was evaluated again formability in the manner described, adhesiveness, tackiness, heat and humidity deterioration As shown in Table 5, all obtained good results.
And the clock produced using the said clock display board was installed in the bathroom used every day for one year, and it was confirmed whether there was no abnormality in the visibility of a display board, but it was in a state without a problem at all.

〔比較例〕

[Comparative example]

On the other hand, when the ultraviolet curable ink-jet ink in the examples was evaluated in the same manner as described in the examples using the inks of the colors 2 and 3 of the experimental examples, as shown in Table 5, the molding was performed. As a result, no results were obtained in which all of the properties of adhesiveness, adhesiveness, tackiness, and high temperature and humidity deterioration were good.

    The present invention can be used in all industrial fields in which a display plate is formed by forming a printed film with an ultraviolet curable inkjet ink.

Claims (4)

Transparent PMMA resin plate on the front, a Viewing plate to be placed under substantially sealed environment arranging the light emitter to at least a portion of the back, the display panel is printed ultraviolet curable inkjet ink on a transparent resin substrate In the display board that has been subjected to predetermined ultraviolet curing,
The ultraviolet curable ink-jet ink has a photoreaction initiator and a photopolymerization reactive composition as essential components, and the photopolymerization reactive composition contains a polyfunctional radical polymerizable oligomer, and then phenoxyethyl acrylate and , one monomer and its remaining of a monofunctional radically polymerizable monomer aromatic monofunctional radically polymerizable monomer, the aliphatic monofunctional radical polymerization monomer and alicyclic of cycloaliphatic monofunctional radical polymerization monomer either of formula monofunctional radical polymerization monomer (however, phenoxyethyl excluded phenoxyethyl acrylate, and the cycloaliphatic monofunctional radical polymerization monomer formulated with phenoxy ethyl acrylate) by a one monomer selected from among a combination according to total 3 kinds of monomers, polyfunctional radically polymerizable oligomer And a phenoxyethyl acrylate, cycloaliphatic monofunctional radical polymerization monomer, the weight ratio of the remaining of the monofunctional radically polymerizable monomer, respectively 0.05 to 0.4: 1: 0.1 to 0.7 : A display board formed by forming a printed film with an ultraviolet curable inkjet ink based on being in the range of 0.1 to 0.7. The alicyclic monofunctional radical polymerizable monomer blended together with phenoxyethyl acrylate is not isocyclopropyl acrylate but the alicyclic monofunctional radical polymerizable monomer corresponding to the other monofunctional radical polymerizable monomer. The display board according to claim 1, wherein   3. A display board according to claim 1, wherein a transparent acrylic cover is disposed in the display direction, and an electronic circuit including an LED is disposed in the back direction.   4. The display board according to claim 1, wherein the display board is displayed by a transparent or translucent acrylic cover that can be visually recognized.