JP2014000734A - Internal printing method by laser marking - Google Patents

Abstract

It is an object of the present invention to provide a printing method for directly printing on a content of a package comprising an exterior body and the contents in the interior space of the exterior body.
The present invention relates to a laser printing method for directly printing on the contents of a packaging body composed of an exterior body and the contents of the internal space of the exterior body, the exterior body being capable of transmitting laser light. Laser printing having a transparent portion, the content having a layer that can be printed by laser irradiation, and printing on the content by laser irradiation through the transparent portion from the outside of the exterior body Regarding the method.
[Selection figure] None

Description

  The present invention relates to a laser printing method for directly printing on the contents of a package by laser irradiation.

The PL Act (Product Liability Act) has been implemented, and various types of printing are required for packaging, labels, and the like. The importance of display is increasing for security to prevent accidents such as forgery and defects, or from the viewpoint of traceability.
Its fields include not only pharmaceutical products but also electronic devices and electronic parts, as well as packaging of various products ranging from foods, daily necessities, and packages, labels, caps, glass bottles, metal cans, and plastic containers. In addition, there is a demand for printing suitable for the product and application.

  Such indications are specifically the model and standard, date of manufacture, expiration date, company logo, production area indication, fertilizer management indication, genetic recombination indication, additive indication, allergy indication, nutrition indication, ingredient indication, This is a label on the packaging that reflects the information added by the consumer, the information that the consumer wants, and the product strategy of the producer and seller, and it is necessary to print according to each product and usage. It has become.

  Conventionally, printing on packaging materials, labels, caps, films, containers, and the like has been performed by plate systems such as gravure printing, flexographic printing, offset printing, and silk screen printing. Further, the expiration date, the date of manufacture, the date and time of the lot number, and the variable printing by the mechanical method are performed by a stamp printing method, an ink jet printing method, a thermal transfer ribbon method, a stamp printing method, and the like.

  In addition to variable characters, when performing production area display, fertilizer management display, nutrition display, component display, etc., it is inevitable that the lot will be small even if it is not variable printing. In order to reflect market needs and product strategies, it becomes a small quantity and a wide variety, but if you do it with a plate method, you will have to prepare a lot of expensive plates, and in addition to the plate cost, the management of the plate is extremely high Costly and cumbersome work.

Due to the recent decline in the number of households due to the declining birthrate and the number of nuclear families, small-packs are being packaged individually. When displaying the above variable characters, not only large bags but also individual packages can be displayed. It has been demanded. Furthermore, when packaging these displays after printing, there is a problem that it takes time from printing to shipping as the number of processes increases by individual packaging.
Also, from the viewpoint of security, it is required that printing can be performed on demand without directly touching the contents. Recently, there are many packaging bodies in which the contents individually packaged are put in an outer package such as a film or a box to protect the merchandise. In this case, it is difficult to print necessary information later on the surface of the contents. There is a need for a printing method that enables individual information to be marked on the surface of the contents immediately after shipment after the contents are put into an outer package and sealed, and that facilitates product inventory, delivery, and distribution management.

JP2007-055110A JP2007-313876

  The present invention, in a package comprising an outer package having a transparent part capable of transmitting laser light and a content having a layer printable by laser irradiation, by irradiating the laser through the transparent part from the outside of the package, This is a laser printing method for directly printing on the contents. By selecting the wavelength of the laser beam, it is possible to print on the contents without damaging the outer package.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a laser printing method for directly printing on the contents of a package comprising an exterior body and the contents of the internal space of the exterior body.

  That is, the present invention relates to a laser printing method for directly printing on the contents of a packaging body composed of an exterior body and the contents of the internal space of the exterior body, wherein the exterior body is a transparent portion through which laser light can be transmitted. And the contents have a layer that can be printed by laser irradiation, and the contents are printed by irradiating laser from the outside of the exterior body through the transparent portion. .

  Furthermore, the present invention relates to the laser printing method, wherein the layer that can be printed by laser irradiation is a printed layer.

  Furthermore, the present invention relates to the above laser printing method, wherein the layer printable by laser irradiation contains a color former that develops color by laser irradiation.

  Furthermore, the present invention relates to the laser printing method described above, wherein the content has a laminate structure comprising a surface protective layer of a transparent plastic film and a layer capable of printing by laser irradiation.

  Furthermore, the present invention relates to the laser printing method, wherein the contents have a label or a seal part, and the label or the seal part has a layer that can be printed by laser irradiation.

  Furthermore, the present invention relates to the laser printing method described above, wherein the outer package is a plastic film substrate, and the content is any one of paper, aluminum foil, or a plastic film substrate.

  Furthermore, the present invention relates to the laser printing method, wherein the wavelength of the laser beam is 532 nm to 1064 nm.

  In the laser printing method of this aspect, the exterior body has a transparent portion that can transmit laser light, and the contents have a layer that can be printed by laser irradiation, so that direct printing is possible without taking out the contents. is there. Further, it cannot be rubbed, rewritten or cut from the outside, which is useful from the viewpoint of preventing impersonation.

  The exterior body in the present invention is not particularly limited as long as it has at least a transparent portion that transmits laser light or a transparent portion is provided, and examples thereof include plastic film, paper, metal foil, and glass. . In the present invention, a plastic film is particularly preferable.

  The thickness of the base material constituting the outer package is not particularly limited, but the transparent portion of the base material that can transmit laser light needs to have a thickness that can sufficiently transmit laser light. If it is too thick, scattering of the laser beam and reduction of the transmission intensity occur, and it is difficult to obtain a sufficient print density.

  As the base material of the exterior body, in the plastic film, low density polyethylene, unstretched and stretched polypropylene, polyethylene terephthalate, nylon, polystyrene, polyvinyl chloride, polycarbonate, polyvinyl alcohol film, and the like, polypropylene, polyester coated with polyvinylidene chloride and the like, Examples of the film include nylon and cellophane.

  A heat-shrinkable film can also be used as the plastic film. Examples of the heat-shrinkable film include polyester and styrene. Further, a vapor deposition film obtained by vapor-depositing aluminum, silica, gold or the like on a film or the like can also be used. The above-mentioned substrate can be used as a plastic molded product in addition to a film.

  Art paper, coated paper, high-quality paper, Japanese paper, synthetic paper, and the like can be used as the base material of the exterior body. As the metal foil, aluminum foil or the like can be used, and a thickness suitable for printing, for example, a thickness of 5 to 150 μm can be used. Known glass can be used, but when laser printing is performed through the glass itself, it is necessary to appropriately select the thickness and transparency.

  These base materials may be used alone or as a composite base material laminated with the same kind or different kinds of base materials via an adhesive or the like, but have a transparent portion capable of transmitting laser light. It is necessary.

  The transparent part that can transmit laser light is (1) a transparent film that can transmit laser light in the case of a plastic film, and an unprinted part if it has a printed part on a film. Corresponds. (2) In the case of paper and metal foil, the exterior body made of those base materials has an opening so that the laser beam can be transmitted, and the opening is made of a transparent film, glass or the like that can transmit the laser beam. It is preferable that it is sealed. (3) In the case of glass, it is preferable to have transparency and thickness that allow laser light to pass through. When decoration is given to the front and back of the glass, the undecorated part corresponds.

Next, the contents will be described.
The contents are: (1) Products, articles, items, etc. (hereinafter referred to as “included items”) provided to consumers and customers in sachets and small boxes; (2) Enclosed items as films, especially shrink films Etc., such as those in which part or all of the inclusions are wrapped in close contact with each other, (3) those in which the label or seal is attached to the surface of the inclusions, or (4) those in which these are combined.

  The layers that can be printed by laser irradiation of the contents are, as shown in the above example, (1) the sachets and small boxes have a printable layer, and (2) the shrinkable film has a printable layer. (3) The label and the seal have a printable layer. (4) A label having a printable layer on a small bag or a small box, or a sticker attached.

  Layers that can be printed by laser irradiation are: (1) laser color printing ink containing a laser color former, printing layer formed from coating liquid, coating layer, (2) film or sheet capable of laser color development, for example, laser Examples thereof include films and sheets kneaded with color formers, labels and seals made of (3) (1) or (2). Preferably, (1) printing ink capable of laser printing, a printing layer formed from a coating liquid, and a coating layer.

  Layers that can be printed by laser irradiation include substrates that can easily develop color by laser irradiation without using a color former, such as resin layers such as vinyl chloride-vinyl acetate copolymer, nitrified cotton, and vinyl chloride resin. Can be mentioned.

  As the laser color former, for example, one or more materials selected from (1) simple metal, (2) metal salt, (3) metal hydroxide, (4) metal oxide, and the like can be used. It is.

(1) Examples of simple metals include iron, zinc, tin, nickel, copper, silver, and gold.

(2) Metal salts include copper carbonate, nickel carbonate, manganese carbonate, cobalt carbonate, lanthanum carbonate, magnesium nitrate, manganese nitrate, iron nitrate, cadmium nitrate, zinc nitrate, cobalt nitrate, lead nitrate, nickel nitrate, copper nitrate , Palladium nitrate, lanthanum nitrate, magnesium acetate, manganese acetate, cadmium acetate, zinc acetate, cobalt acetate, lead acetate, nickel acetate, copper acetate, palladium acetate, copper chloride, iron chloride, cobalt chloride, nickel chloride, silver chloride, chloride Zinc, copper phosphate, iron phosphate, cobalt phosphate, copper pyrophosphate, copper sulfate, iron sulfate, cobalt sulfate, copper oxalate, iron oxalate, cobalt oxalate, copper benzoate, iron benzoate, cobalt benzoate And copper phosphonate having an aromatic ring.

(3) Examples of metal hydroxides include copper hydroxide, aluminum hydroxide, magnesium hydroxide, zinc hydroxide, antimony hydroxide, cobalt hydroxide, nickel hydroxide, iron hydroxide, and lanthanum hydroxide. .

(4) Metal oxides include silicon oxide, aluminum oxide, iron oxide, magnesium oxide, cobalt oxide, lead oxide, tin oxide, indium oxide, manganese oxide, molybdenum oxide, nickel oxide, copper oxide, palladium oxide, oxidation Examples thereof include lanthanum, antimony-doped tin oxide (ATO), indium-doped tin oxide (ITO), synthetic zeolite, natural zeolite, copper-molybten complex oxide (42-903A, manufactured by Tocan Material Technology Co., Ltd.), and the like. As the metal oxide, mica, montmorillonite, smectite, etc. having a layered structure can also be used.

  A preferred laser color former in the present invention is copper-molybten complex oxide (42-903A, manufactured by Toago Material Technology Co., Ltd.). This compound has particularly strong self-coloring properties, and the resin in the vicinity of the compound is also black. Therefore, printed matter with very good visibility can be obtained.

  The layer that can be printed by laser irradiation is preferably formed from a laser color printing ink and a coating liquid. The layer capable of being printed by laser irradiation is such that the laser color former is contained in an amount of 0.3 to 50 parts by weight in 100 parts by weight of the solid matter of the laser color printing ink or coating liquid for forming the laser color layer. This is preferable from the viewpoint of the balance between the coating strength of the laser coloring layer, the cohesive strength and the coloring property. Particularly preferred is 1 to 40 parts by weight.

  If it is less than 0.3 parts by weight, the color developability is inferior although there is cohesion as a film. On the other hand, when the amount exceeds 50 parts by weight, the strength and cohesive strength of the film are lowered, the bending resistance of the recording material laminated by laser irradiation is lowered, and in some cases, the layers are peeled off.

  When a color pigment is used in the laser color printing ink and coating liquid in addition to the laser color former, the clarity, contrast, and visibility can be improved as the background of the printed matter. In the laser color former used in the present invention, it is possible to obtain a print layer having high visibility of laser colorability by using a color pigment such as yellow, red, indigo, or white pigment as necessary. In particular, when titanium oxide is used as a white pigment and used as a part or all of the coloring pigment of the printing ink forming the laser coloring layer, a printed matter with excellent visibility can be obtained. Both anatase and rutile types can be used as titanium oxide.

  The ratio between the laser color former and the color pigment is preferably 30:70 to 1:99. When the ratio of the laser color former is less than 1:99, the color developability is inferior. On the other hand, when the ratio of the laser color former is more than 30:70, the strength and cohesive strength of the film are lowered, and the bending resistance of the laminate is lowered by laser irradiation, and in some cases, the layers are peeled off. More preferably, it is 15: 85-3: 97.

  Binder resin that constitutes a layer that can be printed by laser irradiation, for example, cellulose, methylcellulose, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol, polyacrylamide, polyacrylic acid, casein, gelatin, styrene / maleic anhydride copolymer Examples thereof include salts, isobutylene / maleic anhydride copolymer salts, polyacrylic acid esters, polyurethane resins, and acrylic / styrene resins. Solvent type resins include styrene / maleic acid, acrylic / styrene resin, polystyrene, polyester, polycarbonate, epoxy resin, polyurethane resin, polybutyral resin, polyacrylate ester, styrene / butadiene copolymer, styrene / butadiene / acrylic acid copolymer Examples include polymers, polyvinyl acetate, vinyl chloride / vinyl acetate copolymers, and nitrified cotton. These resins can be obtained singly or by mixing two or more.

  Among these resins, it is preferable to use one or more resins selected from urethane resins, vinyl chloride / vinyl acetate copolymers, nitrified cotton, and the like. In particular, a urethane resin is preferably used as a laminate because it has good adhesion to a film and is excellent in thermal relaxation. In addition, vinyl chloride / vinyl acetate copolymer and nitrified cotton have good color developability by laser and improve color developability as a printing layer and a coating layer even if the laser color former has poor laser absorbability.

  A curing agent can be used in combination for the purpose of improving the film strength, heat resistance, water resistance, solvent resistance, etc. of the layer that can be printed by laser irradiation. As the curing agent, isocyanate, oxazoline, carbodiimide, ethyleneimine, and the like can be used. From the viewpoint of film strength and film physical properties, isocyanate-based curing agents are preferred. Of the isocyanate curing agents, those having 3 or more functional groups are particularly good. When these isocyanate curing agents are combined with a resin having a hydroxyl group, the laser irradiation resistance is improved, and a font having an excellent surface state can be obtained.

Laser coloring printing inks that form layers that can be printed by laser irradiation, coating liquids include pigment dispersants, antifoaming agents, leveling agents, waxes as needed to improve printability, coating suitability, and film properties. A lubricant, a silane coupling agent, an antiseptic, a rust inhibitor, a plasticizer, an ultraviolet absorber, a flame retardant, and the like can be given.
The type and amount of these additives can be appropriately selected depending on the printing method, printing substrate, and printing conditions.

  In addition, a photocurable printing ink can also be used as the laser coloring printing ink. Specifically, unsaturated polyester resins, acrylate resins, polyene / polythiol resins, spirane resins, epoxy resins, aminoalkyd resins, diallyl phthalate resins, unsaturated polyester resins, furan resins, etc. An ultraviolet curable monomer, a prepolymer, a photopolymerization initiator, and a laser color former are used.

  The layer that can be printed by laser irradiation comprises a printing layer and a coating layer, and preferably has a surface protective layer of a transparent plastic film. As the transparent plastic film, it can be used as it is if it is transparent among the plastic films used for the substrate. In particular, polyethylene terephthalate (PET), nylon (Ny), stretched polypropylene (OPP) and the like are preferable.

  The thickness of the transparent plastic film is not particularly limited, but a film usually used for printing can be applied as it is. For example, in the case of PET, 12 to 40 μm, in the case of Ny, 10 to 40 μm, and in the case of OPP, 20 to 50 μm are suitably used. These transparent plastic films are laminated using a known anchor coating agent and adhesive.

  In addition to a surface protective layer made of a transparent plastic film, a surface protective layer made of an ultraviolet / electron beam curable resin coating solution or a surface protective layer formed by heat drying is also applicable.

  As the base material of the contents, the base material used for the outer package can be appropriately selected depending on the application. In the case of labels and seals, it is sufficient that they have a printed layer that can be colored by laser irradiation, a base film, a surface protective layer with a transparent plastic film, if necessary, and the contents through an adhesive layer and an adhesive layer. It is affixed to the surface.

  The contents preferably have a printing layer containing a color former that develops color with a laser. It is more preferable that the contents have a laminate having a transparent plastic film as a surface protective layer.

The laser printing method by laser irradiation is performed with a known laser printing apparatus or laser marker. For example, a carbon dioxide laser (10640 nm), a YAG laser (1064 nm), a YVO ₄ laser (1064 nm), a green laser (532 nm), or the like can be used. In particular, when the wavelength of the laser light is 532 nm to 1064 nm, clearer printing is possible.

Examples of the production of contents having a printable layer by laser irradiation and the printing method by laser irradiation through the outer packaging are as follows: (1) Production of laser color printing ink Paint laser colorant, pigment, organic solvent and binder resin Disperse using a conditioner (manufactured by Red Devil), ball mill, sand mill (such as “Dyno mill” manufactured by Shinmaru Enterprises), attritor, pearl mill (such as “DCP mill” manufactured by Eirich), coball mill, homomixer, etc. . When using media in the disperser, it is preferable to use glass beads, zirconia beads, alumina beads, magnetic beads, styrene beads, or the like.

(2) Printing of laser coloring ink In order to improve the visibility, for example, the above-mentioned laser coloring printing ink contains a white pigment or printing ink having a hue different from that of the laser coloring layer is directly overprinted on the laser coloring layer. It is also possible to do this.
The laser color-developing layer is printed on the whole or a part of the content substrate and used. The laser color printing ink can be printed by a method such as gravure printing, offset printing, flexographic printing, silk screen printing, and the like. In particular, gravure printing is preferable.

(3) Production of packaging body The printed material is laminated using a film by a known method. Using the laminate, the contents are obtained by making bags and boxes so as to enclose necessary commodities, articles and items.

(4) Manufacture of exterior body These contents are further sealed and packaged by an exterior body such as a film, a plastic molded product, and a box to obtain a package.

(5) Printing by laser irradiation Necessary information is printed on the surface of the contents through the transparent portion of the outer package that can transmit the laser beam. Printing by laser irradiation can be performed in either a stationary state or a moving state. However, when there is a lot of printing information or a complicated shape, printing is preferably performed in a stopped state.
In either case, printing is possible with a commercially available laser irradiation device or laser marker.

  Hereinafter, this embodiment will be described in more detail based on examples. In the examples, parts represent parts by weight. % Indicates% by weight unless otherwise specified.

(Synthesis Example 1) Synthesis of Urethane Resin Polytetramethylene glycol (molecular weight 2000, molecular weight was measured by gel permeation chromatography in a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube. 1000 parts) and 222 parts of isophorone diisocyanate were charged and reacted at 85 ° C. for 5 hours in a nitrogen atmosphere. Subsequently, after cooling to 40 ° C., 82 parts of isophorone diamine, 7.8 parts of di-n-butylamine, 1244 parts of toluene, 1244 parts of methyl ethyl ketone and 573 parts of isopropyl alcohol were added and reacted at 40 ° C. for 5 hours with stirring. The urethane resin thus obtained had a solid content of 30% and a viscosity of 350 cps (25 ° C.).

(Production Example 1) Production of laser color printing ink (1) A mixture of 30 parts of copper / molybdenum composite oxide, 120 parts of urethane resin obtained in Synthesis Example 1 and 10 parts of methyl ethyl ketone was kneaded with a paint shaker, and printing ink was used. Obtained. The obtained printing ink was further diluted with a mixed solvent of methyl ethyl ketone, ethyl acetate and isopropyl alcohol (weight ratio 50:40:10), and adjusted to 17 seconds (25 ° C.) with Zahn Carp # 3 (manufactured by Ransha Co., Ltd.) A laser color printing ink (ink 1) was obtained.

(Production Example 2) Production of white ink 30 parts of titanium oxide (Titanics JR805, manufactured by Teika Co., Ltd.), 120 parts of urethane resin obtained in Synthesis Example 1 and 10 parts of methyl ethyl ketone were kneaded with a paint shaker, and printing ink Got. The obtained printing ink was further diluted with a mixed solvent of methyl ethyl ketone, ethyl acetate and isopropyl alcohol (weight ratio 50:40:10), and adjusted to 17 seconds (25 ° C.) with Zahn Carp # 3 (manufactured by Ransha Co., Ltd.) A white ink (ink 2) was obtained.

<Example 1>
Using a gravure plate with a plate depth of 30 μm on the treated surface side of corona discharge treated PET (“Ester E5102” manufactured by Toyobo Co., Ltd., film thickness 12 μm) as a transparent plastic film substrate, printing speed 50 m / min, drying temperature 60 ° C. A laser color printing ink (ink 1) was printed on the entire surface, and a white ink (ink 2) was overprinted on the entire surface to obtain a printed matter.

  Using the adhesive (EL540 / CAT-RT80 manufactured by Toyo Morton Co., Ltd.), the obtained printed material was bonded with PE (low density polyethylene TUX-FCD manufactured by Tosero Co., Ltd., film thickness 40 μm) as a sealant film to produce a laminate. . Using these laminates, a bag was made so as to enclose a plastic rectangular parallelepiped (model product) of 5 cm long × 5 cm wide × 5 mm high to obtain the contents. In addition, the outermost surface of the content is corona discharge treatment PET which is a transparent plastic film base material, and also has a function as a surface protective layer. Printing by laser irradiation can be performed at any location.

Next, this content was put into a transparent plastic molding container made of PET (polyethylene terephthalate) having a length of 10 cm, a width of 10 cm, and a height of 5 cm to obtain a package (1).
For the package, using a YVO ₄ laser, "Keyence MD-9600", through the transparent plastic molded container of the exterior body was subjected to laser-printed on the contents of the surface by laser irradiation. Evaluation items are visibility and surface condition. The printing conditions are as follows.

Evaluation of visibility (1) Scanning speed = 500 mm / sec (2) Q-switch frequency = 20 kHz
(3) Laser power 80%
(4) Printing content Solid printing of 6mm x 6mm

Surface condition evaluation (1) Scanning speed = 500 mm / sec (2) Q-switch frequency = 20 kHz
(3) Laser power 80%
(4) Printed content “ABC123”

<Example 2>
Example 1 is the same as Example 1 except that the transparent plastic film substrate of the contents is Ny (ON-RT, manufactured by Unitika Co., Ltd., film thickness 15 μm). About the obtained package (2), the printed matter was obtained on the same printing conditions as Example 1.

<Example 3>
The same contents as in Example 1 were made into a bag (exterior body) with a laminate of PET / adhesive / PE to obtain a package (3). About the obtained package (3), the printed matter was obtained on the same printing conditions as Example 1. FIG. The PET, adhesive, and PE used are the same as in Example 1.

  In the packaged bodies (1) to (3) after laser irradiation obtained in Examples 1 to 3, the contents were taken out from the outer package, and the visibility and surface condition of the surface printing were evaluated. Evaluation methods and evaluation criteria are as follows.

(1) Visibility Visibility by laser printing on the surface of the contents was measured with a reflection density (spectral densitometer X-rite 520, manufactured by X-Rite). The results are shown in Table 1. The practical level is 0.40 or more.

(2) Surface state The swelling and peeling state of the contents surface were evaluated in three stages. The results are shown in Table 1. The practical level is 3.
3: There is no swelling on the surface on the laser irradiation side.
2: Swelling is slightly seen on the surface on the laser irradiation side 1: Many swellings are seen on the surface on the laser irradiation side.

Claims (7)

A laser printing method for directly printing on the contents of a package consisting of an exterior body and the contents of the internal space of the exterior body,
The exterior body has a transparent portion that can transmit laser light,
A laser printing method, wherein the content has a layer that can be printed by laser irradiation, and the content is printed by irradiating laser through the transparent portion from the outside of the outer package.   The laser printing method according to claim 1, wherein the layer printable by laser irradiation is a printing layer.   3. The laser printing method according to claim 1, wherein the layer printable by laser irradiation contains a color former that develops color by laser irradiation.   The laser printing method according to any one of claims 1 to 3, wherein the content has a laminate structure composed of a surface protective layer of a transparent plastic film and a layer printable by laser irradiation. The contents have a label or a seal part,
The laser printing method according to claim 1, wherein the label or the sheet part has a layer that can be printed by laser irradiation. The exterior body has a plastic film substrate,
The laser printing method according to any one of claims 1 to 5, wherein the content includes any one of paper, aluminum foil, and a plastic film substrate.   The laser printing method according to any one of claims 1 to 6, wherein the wavelength of the laser beam is 532 nm to 1064 nm.