JP5140356B2 - Ink composition suitable for printing on transparent synthetic resin - Google Patents

Description

  The present invention relates to an ink composition excellent in printability on a transparent synthetic resin. Specifically, the present invention relates to the provision of an ink composition suitable for printing on a transparent synthetic resin for medical use such as an artificial eye or a contact lens.

  The use of transparent synthetic resins as optical materials is increasing year by year. As transparent synthetic resins for optical material applications, acrylic resins, styrene resins, amorphous polyester resins and the like are known. In order to increase the added value of these synthetic resins, a character, a pattern, etc. are given to resin itself, without impairing the transparency. For example, an acrylic resin is generally used as an artificial eye or a contact lens as a medical material, but naturally it is necessary to impart an eye pattern or an iris pattern.

  As a method for imparting an eye pattern to a conventional artificial eye, a method of manufacturing a color photograph obtained by photographing a normal naked eye between acrylic resins (see Patent Document 1), an eye pattern is drawn on an eyeball-shaped resin. And then coating with the same kind of acrylic monomer. However, in these methods, it is necessary to consider that the acrylic monomer does not fade the color photograph, and the operation is complicated.

On the other hand, a technique of a so-called in-mold coating method is disclosed in which an iris pattern is preliminarily provided in a mold and a lens body is polymerized in the production of a cosmetic contact lens (see Patent Document 2). In addition, a technique for applying a pattern to a lens body by inkjet is also disclosed (see Patent Document 3).
Japanese Utility Model Publication No. 2-28219 Special table 2004-516524 gazette Special table 2005-508432 gazette

  When a printed pattern is imparted to the artificial eye or contact lens as described above, a general ink composition may have poor printability on the synthetic resin of the ink itself, resulting in unclear characters and patterns. In addition, since an organic solvent is used for adjusting the ink, depending on the organic solvent, the synthetic resin itself may be eroded and transparency may be impaired. Furthermore, medical materials such as artificial eyes and contact lenses are in contact with the human body, and when an organic solvent is used in the ink composition, the safety thereof is also a concern.

  An object of the present invention is to provide an ink composition excellent in printability on a transparent synthetic resin without using an organic solvent that may remain during adjustment.

  The present invention is an ink composition suitable for printing on a transparent synthetic resin comprising a urethane (meth) acrylate resin, a vinyl ether having one vinyl group, and a colorant.

  The ink composition according to the present invention is excellent in transferability and durability to a transparent synthetic resin, so that clear characters and patterns can be imparted, and since no organic solvent is used, there is no contamination of the transparent synthetic resin itself, In addition, the organic solvent is not adversely affected.

  The present invention uses a urethane (meth) acrylate resin as a main component. A commercially available urethane (meth) acrylate resin can be used, but the viscosity is 10,000 due to the relationship with other components, particularly the adhesiveness with the applied transparent synthetic resin and the colorant used. It is good to use the thing of -70,000 mPa * s in 30-60 wt% in an ink composition, Preferably it is 45-55 wt%. If it is less than 30 wt%, the adhesion to the transparent synthetic resin that is the object to be colored and the dispersion of the colorant in the ink composition will be insufficient. If it exceeds 60 wt%, not only the coloring effect is lowered, but also the viscosity of the ink composition is increased, so that the handling becomes troublesome.

  The vinyl ether in the present invention is effective in adjusting the viscosity at the time of adjusting the ink, but is combined with other components in the ink cured product during the reaction as the ink composition. The vinyl ether used in the present invention has one vinyl group in the molecule, and specifically, those having a relatively low boiling point such as normal propyl vinyl ether, isopropyl vinyl ether, normal butyl vinyl ether, isobutyl vinyl ether are preferably used. . When a bifunctional divinyl ether compound or a high molecular weight polyvinyl ether compound is used, the effect of adjusting the viscosity cannot be exhibited.

  The amount used depends on the desired composition of the ink composition, but is in the range of 20 to 50 wt%, preferably 30 to 40 wt% in the ink composition due to the relationship with the urethane (meth) acrylate resin and other components. If it is less than 20 wt%, the effect of adjusting the viscosity cannot be expected, and if it is more than 50 wt%, the coloring effect and printability of the ink composition are lowered.

  As the colorant, phthalocyanine blue, phthalocyanine green, iron oxide (yellow, red, brown), titanium oxide, dye pigments such as vat dyes, and the like can be used. Can be granted. For example, black titanium oxide is used for black, and white titanium oxide is used for white. The amount used thereof is preferably 10 to 15 wt% in the ink composition as a result of examination from the performance as an ink composition. If the amount is too large, the dispersibility of the colorant and the adhesion of the ink composition itself to the object to be colored are lowered.

  The crosslinkable monomer improves effects such as fastness after curing of the ink composition, and is preferably a bifunctional acrylic type, and specifically includes ethylene glycol dimethacrylate and the like. The amount used may be 3 to 5 wt% in the ink composition although it depends on the desired composition of the ink composition.

  Since the ink composition of the present invention has a structure capable of photopolymerization, it can be carried out without using a polymerization initiator. An appropriate amount of oxide-based material may be used.

  As a method for preparing the ink composition of the present invention, the respective components may be sequentially weighed. However, it is preferable to first weigh the vinyl ether compound, add the colorant to this, and mix it, since the colorant can be uniformly dissolved. Thereafter, a urethane (meth) acrylate resin may be added and stirred to dissolve the whole uniformly. At this time, a crosslinkable monomer can be added together with the urethane (meth) acrylate resin.

  Since the ink composition of the present invention can give letters and patterns without damaging the transparent synthetic resin that is the object to be colored, it can be printed as it is, or letters and patterns can be given by other methods. I can do it. For example, a clear pattern can be obtained by printing a desired pattern on a synthetic resin film with a tampo printer and heating the prepared ink composition at about 80 ° C. for about 10 hours. The synthetic resin film provided with this pattern can be suitably used as a color pattern portion in a conventionally known in-mold coating method.

  Specifically, when producing artificial eyes or contact lenses for cosmetics, an eye pattern is printed on a transparent synthetic resin film using the ink composition of the present invention, and then placed in a mold. If the mold is filled with an acrylic monomer that is a raw material for the artificial eye or contact lens and polymerized, a colored pattern can be easily imparted.

  Examples of the transparent synthetic resin suitably used in the present invention include acrylic resins, styrene resins, amorphous polyester resins, and cellulose resins that are generally known. Methacrylate (PMMA), polyethylene terephthalate (PET), triacetyl cellulose (TAC), polycarbonate (PC) and the like are preferably used.

Example 1
After dissolving 13 wt% of black titanium oxide (Ako Kasei Co., Ltd., Tilac D) in 35 wt% of normal butyl vinyl ether (Nippon Carbite Industries, Ltd., NBVE), urethane acrylate (Shin Nakamura Chemical Co., Ltd., NK Oligo) 48 wt% of U-15HA), 4 wt% of ethylene glycol dimethacrylate (Mitsubishi Rayon Co., Ltd., acrylic ester ED) as a crosslinkable monomer, and stirred and mixed with a magnetic stirrer, 2,2-azo as an initiator An ink composition was obtained by adding 0.3 wt% of bisisobutyronitrile (Wako Pure Chemical Industries, Ltd.) to the total amount. Using this ink composition, an iris pattern of the eye was printed on a PET film with a tampo printer, and placed in a hot air circulating dryer adjusted to 80 ° C. for 10 hours to cure the ink composition.

  When the appearance of the printed surface of the film was visually confirmed, it was a clear printed surface, the color was not lost, the iris pattern was clear, and the transferability was good. Further, as a durability test of the printed surface, the printed surface was left for 90 days at a relative humidity of 95% and 40 ° C., but no loss or fading of the printed surface was observed. Furthermore, as a severe test of the printed surface, it was immersed in hot water at 70 ° C. for 36 hours, but no loss or fading of the printed surface was observed.

(Example 2)
The film obtained in Example 1 was placed on an artificial eye mold with the iris-patterned printing surface facing upward, and an acrylic monomer as a raw material for artificial eye was charged from above and polymerized by heating to produce an artificial eye. . The iris pattern of the obtained artificial eye was clear without being affected by the raw material for the artificial eye. Further, the adhesion between the film provided with the iris pattern and the artificial eye was good.

(Comparative Example 1)
48 wt% urethane acrylate (Shin Nakamura Chemical Co., Ltd., NK Oligo U-15HA), 35 wt% triethylene glycol divinyl ether (Nippon Carbite Industries, Ltd., TEGVE) as a vinyl ether compound having vinyl groups at both ends. , Black titanium oxide (Ako Kasei Co., Ltd., Tilac D) 13 wt%, ethylene glycol dimethacrylate (Mitsubishi Rayon Co., Ltd., acrylic ester ED) 4 wt%, 2,2-azobis as a crosslinkable monomer An ink composition was obtained in the same manner as in Example 1, except that 0.3 wt% of isobutyronitrile (Wako Pure Chemical Industries, Ltd.) was used. Using this ink composition, an iris pattern of the eye was printed on a PET film with a tampo printer and placed in a hot air circulating dryer at 80 ° C. for 10 hours in the same manner as in Example 1 to cure the ink composition.

  When the appearance of the printed surface of this film was visually confirmed, the iris pattern was slightly unclear and hard as compared with Example 1, and it was not able to withstand use because it fell off when touched with a finger.

Claims (2)

Urethane (meth) acrylate resin ;
N-propyl vinyl ether, isopropyl vinyl ether, vinyl ether having one vinyl group selected from the group consisting of n-butyl vinyl ether and isobutyl vinyl ether; and <br/> transparent synthetic resin ink composition comprising a colorant. Wherein, transparent synthetic resin ink composition according to claim 1, characterized in that it is a medical material.