JP2006056049A - Label printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a label printing method in which a photopolymerization initiator does not permeate into a container even when a polyethylene container is used.
SOLUTION: A heat-shrinkable film 26 attached to the side surface of a polyethylene container body 16 is provided, and ultraviolet curable ink is printed on the back side of the film 26. Thereafter, the ultraviolet ray is irradiated to the printing portion in a nitrogen atmosphere in which oxygen is blocked to cure the ultraviolet curable ink. The ultraviolet curable ink is a white ink which is difficult to transmit light with a pigment of titanium oxide powder.
[Selection] Figure 1

Description

  The present invention relates to a method for printing a label attached to an eye drop container.

2. Description of the Related Art Conventionally, small containers for containing eye drops are configured by a synthetic resin container body and a cap detachably attached to an extraction port formed in the container body. The container body and the cap are sealed with a sealing label on which a drug name, a trademark, and the like are printed. This sealing label is made of a heat-shrinkable resin film in a cylindrical shape, and is heat-shrinked and attached to the container body. The sealing label is formed with a sewing line at the boundary between the container body and the cap, and is divided into a label part that covers the container body and a separation part that covers the cap with the sewing line as a boundary. The name of a medicine, a trademark, etc. are printed on this label part and affixed to the container body. Further, the separation part is cut off when the cap is opened.
JP 2001-130621 A

  In general, the eye drop container is preferably a relatively soft PE (polyethylene) resin from the viewpoint of usability, but the soft low-density polyethylene resin has a problem that it has a rough molecular structure and allows air, water vapor, and other chemical substances to pass therethrough. In particular, some volatile substances in the ink on the back side of the label attached to the eye drop container may pass through the container main body and migrate into the eye drop although it is a very small amount. As the chemical substance to be transferred, there is a photopolymerization initiator for curing the ultraviolet curable ink. This photopolymerization initiator absorbs ultraviolet rays to generate radicals, crosslinks oligomers and monomers in the ultraviolet curable ink to polymerize them, and cures the ink.

  On the other hand, there are PP (polypropylene) resin, PET (polyethylene terephthalate), PC (polycarbonate), etc. as the non-permeable resin as described above, but containers using this resin are relatively hard and inject eye drops. It is difficult to use as an eye drop container because it is difficult and operability is poor.

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a label printing method in which a photopolymerization initiator does not migrate through a container even when a polyethylene container is used.

  The present invention provides a heat-shrinkable film to be affixed to the side surface of a polyethylene container body, prints an ultraviolet curable ink on the back side of the film, and then prints the printed portion in an atmosphere in which oxygen is blocked. Is a label printing method in which UV rays are irradiated to cure the UV-curable ink.

  The ultraviolet curable ink is a white ink which is a titanium oxide powder pigment and hardly transmits light. The ultraviolet irradiation is performed in a nitrogen atmosphere. The label is irradiated with ultraviolet light continuously in an atmosphere where the nitrogen gas pressure is slightly higher than atmospheric pressure.

  According to the label printing method of the present invention, the curing of the ultraviolet curable ink is fast and reliable, the amount of the photopolymerization initiator used can be greatly reduced, the photopolymerization initiator does not penetrate into the container, These impurities are not transferred into the container. Therefore, it is possible to use a polyethylene container that is soft and has a good feeling of use, and can provide an easy-to-use and highly safe eye drop container.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 3 show an embodiment of the present invention. A sealing label 12 attached to an eye drop container 10 of this embodiment is made of a transparent heat-shrinkable resin such as polyethylene. The sealing label 12 is wound around the outside of a small eye drop container 10 for storing eye drop liquid and attached in a cylindrical shape. The eye drop container 10 includes a container body 16 made of polyethylene and a cap 18 attached to an extraction port formed in the container body 16. A sealing label 12 on which a drug name, a trademark, and the like are printed is attached to the eye drop container 10 and sealed.

  The sealing label 12 is heat-shrinked and is attached to the eye drop container 10 exactly. A horizontal sewing line 20 is formed on the sealing label 12 between the container body 16 and the cap 18. The horizontal sewing machine line 20 is divided into a label portion 22 that covers the container body 16 and a separation portion 24 that covers the cap 18.

  The label portion 22 is printed with a drug name, a trademark, and the like, and an adhesive is applied and attached to the side surface of the container body 16. Further, the separation part 24 is separated by the horizontal perforation 20 when the cap 18 is opened.

  When the sealing label 12 is unfolded, it becomes a film body 26 made of a film having the shape shown in FIG. The film body 26 shown in FIG. 2 is a developed view of the back side surface of the film body 26. The film body 26 is formed in a rectangle of a size that covers and covers the eye drop container 10, and the winding direction is the longitudinal direction. Both end portions in the longitudinal direction of the film body 26 are overlapping portions 28 where the end portions of the film body 26 overlap and are bonded together, and the overlapping portion 28 and the lower portion of the horizontal sewing machine line 20 can be adhered by an adhesive. The adhesive portion 30 is formed. The film body 26 is securely attached to the container body 16 by the adhesive portion 30.

  White ink is applied to the entire surface of the lower surface of the adhesive portion 30 on the back surface of the label portion 22 corresponding to the deformed portion of the container body 16. This is printing as a base for making it easy to understand the printing of characters and marks such as drug names and trademarks.

  Next, a method for printing the sealing label 12 will be described. In this printing method, ultraviolet curable white ink is printed on the entire surface of the label portion 22 which is the printing portion of the sealing label 12 or on an appropriate portion. White ink contains a pigment of titanium oxide powder, and hardly transmits ultraviolet rays or visible light. This white ink contains 2 to 7% of a photopolymerization initiator for promoting ultraviolet curing. As described above, the photopolymerization initiator absorbs ultraviolet rays to generate radicals, crosslinks oligomers and monomers in the ultraviolet curable ink to polymerize them, and cures the ink. Examples of the monomer of the ultraviolet curable ink include -2-hydroxyethyl methacrylate and 1,6-hexanediol diacrylate. Examples of the photopolymerization initiator include 2-hydroxy-2methylpropiophenone and 2,2-dimethoxy-2-phenylacetophenone. The molecular weight of these photopolymerization initiators is 150 to 400, and many are 200.

  After printing the white ink on the label portion 22, the printed white ink is cured. Curing is performed by passing the film body 26 of the sealing label 12 through the ultraviolet irradiation device 40 as shown in FIG. At this time, the inside of the irradiation space 44 provided with the ultraviolet lamp 42 of the ultraviolet irradiation device 40 is filled with nitrogen gas. The nitrogen gas pressure in the irradiation space 44 is slightly higher than the atmospheric pressure, so that oxygen does not enter the irradiation space 44.

  Here, the effect of irradiating ultraviolet rays in nitrogen gas will be described. In the photopolymerization reaction of UV curable ink, oxygen in the air inhibits the polymerization reaction of the ink, and the ink in the part in contact with the air is hard to polymerize and cure. Requires about 10 times as much photopolymerization initiator as theoretically required to be contained in the ink. Thus, conventionally, there is a photopolymerization initiator that remains in the ink even after the ink is cured, and the photopolymerization initiator may migrate from the ink through the container body 16 and into the eyedrop liquid. In contrast, by performing ultraviolet irradiation in a nitrogen atmosphere where oxygen is blocked, the polymerization reaction is not subject to oxygen inhibition, and the amount of photopolymerization initiator contained in the ink can be greatly reduced. The photopolymerization initiator in the ink is used for UV curing without waste, and the oligomer and the monomer in the ink can be reliably cross-linked and polymerized and fixed. Therefore, if the UV curable ink is cured by irradiating UV light in an oxygen-blocked atmosphere, no photopolymerization initiator remains in the printed ink, so the photopolymerization initiator passes through the container wall. And will not be mixed into the drug.

  Next, a method for attaching the sealing label 12 will be described. First, the adhesive surface of one overlapping portion 28 is pushed against the side surface of the container body 16 so that the label portion 22 of the film body 26 is positioned on the side surface of the container body 16 with respect to the eye drop container 10 to which the cap 18 is attached. Wrap it around. Then, the overlapping portions 28 of the film body 26 are overlapped and bonded together, and the adhesive portion 30 is adhered to the side surface of the container body 16 to form a cylindrical shape. Thereafter, heat treatment is performed, and the film body 26 is thermally contracted to adhere to the eye drop container 10. At this time, the separation portion 24 of the film body 26 is in close contact with the cap 18, and the upper end portion of the separation portion 24 covers the peripheral edge portion of the upper surface of the cap 18.

  According to the sealing label 12 of this embodiment, the curing of the ultraviolet curable ink is fast and reliable, the photopolymerization initiator does not pass through the container, and other impurities do not pass through the container.

  The label printing method of the present invention is not limited to the above embodiments, and the type of ultraviolet curable ink to be printed on the label portion can be appropriately selected, and the material of the photopolymerization initiator is not limited. Is. Furthermore, the printing method can be applied to an appropriate printing method such as letterpress printing, intaglio printing, stencil printing, and lithographic printing.

  Further, as a method for suppressing the migration of the photopolymerization initiator in the ink, it may be combined with preventing the permeation migration of the container wall by increasing the molecule by chemical modification. As an oxygen blocking method, an inert gas other than nitrogen or other gas may be used.

  Next, examples of the present invention will be described. Here, two types of ink, a commercially available ultraviolet curable white ink (sample 1) and an ultraviolet curable white ink (sample 2) that has been improved in reducing the migration of the photopolymerization initiator to the eye drops, are used for each ink. For the five types of photopolymerization initiators A, B, C, D, and E mixed with each other, the amount of the photopolymerization initiator transferred from the ink into the container was examined.

  In addition, the analysis test this time was conducted with white ink because, in the case of other color inks in the preliminary test, UV curable ink that was improved in reducing the shift of the photopolymerization initiator to the eye drop side was mixed in the ink. For all types of photopolymerization initiators that were used, the detected amount was less than the analytical measurement limit, and the migration of the photopolymerization initiator was completely suppressed. It carried out about.

  As the sample, a label in which a UV curable white ink containing a predetermined amount of a photopolymerization initiator was printed on the back side of the film was affixed to a polyethylene container, and 5 ml of distilled water was added and sealed.

  As for the photopolymerization initiator, a mixture of the above two types of white ink (samples 1 and 2) with an amount necessary for ultraviolet curing in air (several percent relative to the ink) (sample 1). B) Sample 2-i) and the amount of photopolymerization initiator necessary for UV curing in a nitrogen atmosphere, which is a mixture of one-tenth of Document A (Sample 1-b, Sample 2- B) was made respectively. The printing method of this example was flexographic printing, and the white ink had a titanium oxide pigment and was printed using a low-viscosity quick-drying ink with high fluidity.

  Samples 1-i and 2-i were irradiated with ultraviolet rays in air, and Samples 1-b and 2-ro were irradiated with ultraviolet rays in a nitrogen atmosphere. Each material was well fixed with ink by UV curing.

  Table 1 shows the results of an acceleration test in which the penetration of the photopolymerization initiator into the container was examined using these samples. The numerical values in Table 1 indicate the weight (mg / l = ppm) of the photopolymerization initiator transferred to the distilled water in the container. In this experiment, each sample was placed in a thermostatic chamber at 60 ° C. for 7 days, and then a certain amount of water in the container was taken out and measured with a high performance liquid chromatograph mass spectrometer.

  As a result, the photopolymerization initiator is usually used for both the commercially available UV curable white ink (Sample 1) and the UV curable white ink (Sample 2) that has been improved in reducing the migration of the photopolymerization initiator to the eye drops. When UV irradiation is performed on the UV curable ink in a nitrogen atmosphere (Sample 1-B, Sample 2-B), the amount of the photopolymerization initiator transferred into the container is Compared with the case of irradiation with ultraviolet rays in the air (Sample 1-i, Sample 2-i), the total is reduced.

  In addition, for the UV curable white ink (Sample 2) that has been improved to reduce the shift of the photopolymerization initiator to the eye drops, the photopolymerization initiator is reduced to one-tenth of the normal and UV curable ink in a nitrogen atmosphere. The sample was irradiated with ultraviolet rays (Sample 2-B), and all of the five types of photopolymerization initiators were below the measurement limit, and the migration of the photopolymerization initiator to the eye drop side could be completely suppressed.

  Therefore, by irradiating the UV curable ink with UV light in a nitrogen atmosphere where oxygen is blocked, the ink can be printed with a small amount of photopolymerization initiator and the chemical substance can be prevented from moving into the container. It was confirmed that it was possible. Further, according to this printing method, since reliable ink curing can be obtained with the use of a small amount of photopolymerization initiator, even in printing using highly fluid ink such as flexographic printing, the photopolymerization initiator in the ink is used. Can be reliably prevented from moving to the container contents. In addition, it can be said that the same effect can be obtained in other printing methods and colors of ultraviolet curable ink.

It is a perspective view of an eye drop container which gave a sealing label of one embodiment of this invention. It is an expanded view of the sealing label of this embodiment. It is a schematic sectional drawing of the ultraviolet curing device used for the sealing label of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Eye drops container 12 Sealing label 16 Container main body 18 Cap 20 Horizontal sewing machine wire 22 Label part 24 Separation part 26 Film body 30 Adhesive part

Claims (4)

  A heat-shrinkable film is provided on the side of the polyethylene container body, and UV-curable ink is printed on the back side of the film. And curing the ultraviolet curable ink.   The label printing method according to claim 1, wherein the ultraviolet curable ink is a white ink that hardly transmits light.   The label printing method according to claim 1, wherein the irradiation with ultraviolet rays is performed in a nitrogen atmosphere. 4. The label printing method according to claim 3, wherein the ultraviolet irradiation of the label is continuously performed in an atmosphere in which a nitrogen gas pressure is slightly higher than atmospheric pressure.

Images