JP4853340B2 - Laser marking method for film material and laser marking method for paper container - Google Patents

Description

The present invention relates to a laser marking method for a film of a laminate of a film material capable of laser marking , and in particular, an ink comprising a general safe pigment and resin system that does not contain a coloring pigment having poor safety and hygiene suitability such as a dye precursor. In the selection and contrivance of the resin component and the limitation of the wavelength of the laser beam used at the time of laser marking, it is possible to record information by coloring the ink layer in the layer without scraping the surface film of the film laminate, excellent abrasion resistance, relates to laser marking method of the full Ilm material visibility you allow satisfactory printing representation.

  In the conventional technology, an ink jet method in which a fast-drying acrylic resin-based ink is attached to an adherend is used for printing of a shelf life on a package of food or the like, or for a production process or product management record such as a production number. Printing is mainstream.

  Ink jet printing has a problem that the adhesion state is easily affected by the surface condition of the adherend, for example, surface wettability, surface contamination, etc., and there is a problem that printing failure occurs due to ink clogging on the apparatus side, for example, an ink jet nozzle. is there.

  Ink jet printing has a problem of friction resistance because the printing ink is formed in a convex shape on the surface of the adherend. For example, printing is done by rubbing the product and product, or the product and cardboard boxes. There is a problem of ink peeling.

  In the printing by laser marking, since the printing is performed by cutting the surface base material or the intermediate base material, the wear resistance is good, and it is particularly used as a printing method on the surface of electronic parts and home appliances.

In the field of packaging, especially in the field of soft packaging materials in which resin-based thin films are laminated, printing with a carbon dioxide laser (CO ₂ laser) having a wavelength of 10 μm units causes, for example, generation of through-holes and burned debris on the surface substrate May lower the physical strength of the substrate itself. Moreover, it may lead to deterioration of the package strength due to penetration or the like from the through hole.

Printing with a YAG laser or YVO ₄ laser with a wavelength of 1000 nm unit has a small effect on the package strength because it passes through the surface substrate and prints on the ink layer or metal layer in the intermediate layer. A high urethane resin type ink layer has a problem in that the visibility of printing is inferior without only developing the color simply by shaving the ink layer.

For example, Patent Document 1 proposes a method using a dye precursor or a coloring pigment as a measure for improving the visibility of printing. In the prior art, an ink for an ink layer capable of laser marking has been proposed. The price of the ink is high, and the ink composition contains additives and has a problem of poor safety and hygiene.

  Current inks that can be laser-marked include dye precursors and the like, and include special coloring pigments, which may pose problems for safety and hygiene due to the use of safe pigments and resin systems. In the ink, it is necessary to make efforts to solve problems such as selection and contrivance of resin components having excellent color developability and limitation of the wavelength of laser light used for laser marking. It is important to optimize the laser layer that can be laser-marked, which is cheaper and has good visibility. It is.

The known literature is described below.
JP 2003-261882 A

An object of the present invention, general free of dye precursor such as safety and health properly poor color pigment, a ink consisting safe pigments and resin systems, during laser marking, a surface film substrate of the film laminate the ink layer was developed can be recorded information in the layer without scraping, excellent wear resistance, provides a laser marking method of the full Ilm material visibility you allow good printed representation It is to be.

The resin composition of the ink layer to be selected and laminated from general-purpose resin materials suitable for hygiene and safety in the field of paper containers with soft packaging materials such as lids and pouch bags and film materials as the front substrate A number of implementation tests were conducted on the subject of an invention of a laser marking method for a laminated film excellent in laser marking suitability that can be provided at a low cost.

The invention according to claim 1 of the present invention is a film material capable of laser marking, which is a film laminate for recording information using laser light, and a component contained in a resin binder on one surface of a supporting base film. Is a film laminate in which an ink layer of vinyl chloride / vinyl acetate copolymer is laminated, wherein the vinyl chloride / vinyl acetate copolymer contained in the resin binder contains 60% by weight or more, and the ink layer The main pigment component contained in Titanium Oxide is titanium oxide, and the pigment content is 30% by weight or more of the solid content of the ink. For a film material capable of laser marking , a YGA laser or YVO ₄ laser is applied to the ink layer. in used laser marking method of the full Ilm material you and performs recording of information with laser beams of the emission wavelength of 1064 nm That.

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The invention according to claim 2 of the present invention, the substrate film is a transparent plastic film, according to claim 1 Symbol placement of full, characterized in that the aluminum foil is laminated through an adhesive ink layer laminated side This is a laser marking method for film materials.

The invention according to claim 3 of the present invention is a film container capable of laser marking by a laser marking method for a film material according to claim 1 or 2 in a paper container provided with a film material capable of laser marking as a front substrate. Is a method of laser marking on a paper container , wherein information is recorded by the method .

In the invention according to claim 4 of the present invention, a film material that can be laser-marked by the laser marking method for a film material according to claim 1 or 2 is arranged on the surface of the lid material of the paper container, and information is recorded by this method. a laser marking method on a paper container according to claim 3, wherein the performing.

In the invention according to claim 5 of the present invention, a film material that can be laser-marked by the laser marking method for a film material according to claim 1 or 2 is arranged on the surface of a label material of a paper container, and information is recorded by the method. a laser marking method on a paper container according to claim 3, wherein the performing.

In the invention according to claim 6 of the present invention, a film material that can be laser-marked by the laser marking method for a film material according to claim 1 or 2 is arranged on the surface of a bag of a paper container, and information is recorded by the method. a laser marking method on a paper container according to claim 3, wherein the performing.

According to a seventh aspect of the present invention, a film material that can be laser-marked by the laser marking method for a film material according to the first or second aspect is disposed on the surface of a paper cup of a paper container, and information is recorded by the method. The laser marking method for a paper container according to claim 3 .

With the laser marking method of the full Ilm material of the present invention does not include poor color pigment properly dye precursors such as safety and health, by forming the ink layer using an ink comprising a safe pigments and resin systems, safety properly under environmentally compatible, with excellent wear resistance, visibility can be provided a laser marking method to good printable representation and to that off Ilm material.

With the laser marking method of the full Ilm material of the present invention, by limiting the wavelength of the laser beam used during laser marking, by coloring an ink layer which is in no layers in the cut surface film substrate of the film laminate Information recording can perform the excellent wear resistance, visibility can be provided a laser marking method to good printable representation and to that off Ilm material.

With the laser marking method of the full Ilm material of the present invention, the selection and ingenuity of the resin component, by limiting the wavelength of the laser beam used during laser marking, in a layer without scraping the surface film substrate of the film laminate certain ink layer by coloring can perform recording of information, excellent wear resistance, visibility can be provided a laser marking method to good printable representation and to that off Ilm material.

The laser marking method of the full Ilm material of the present invention will be described below with reference to an embodiment.

FIG. 1 is a partially enlarged side sectional view for explaining an embodiment of a layer structure of a laser-markable film material used in the present invention.

As shown in FIG. 1, a film material 10 capable of laser marking used in the present invention has an ink layer 2, an adhesive layer 3, an aluminum foil 4, a polyethylene layer 5, a hot melt on one side of a PET film 1 as a supporting substrate. It is the film laminated body laminated | stacked on the layer 6 in the order.

The supporting substrate film 1 is a transparent plastic film, and is a film material 10 capable of laser marking used in the present invention in which an aluminum foil 4 is laminated on an ink layer lamination side via an adhesive layer 3.

In the present invention , the ink layer 2 is formed by applying ink to one surface of the PET film 1 of the support substrate and drying by heating. The ink is composed of a pigment, a resin binder, and a solution, and an ink layer in which a component contained in the resin binder is a vinyl chloride / vinyl acetate copolymer is laminated. In the present invention, the vinyl chloride / vinyl acetate copolymer is applied with an ink containing 60% by weight or more of the resin binder solid content to form the ink layer 2.

The main pigment component contained in the ink layer 3 is titanium oxide, and the laser marking used in the present invention in which the ink layer 2 is formed by applying an ink having a pigment content of 30% by weight or more based on the solid content of the ink. Possible film material.

Figure 2 is a side sectional view of a partially enlarged for explaining an embodiment of a laser marking method to full Ilm material of the present invention.

Laser marking method to full Ilm material of the present invention, a predetermined laser irradiation than PET film 1 side, a laser marking method for marking ink layer.

The laser-markable film material used in the present invention is a film laminate that enables recording of information using laser light, and is contained in a resin binder on one surface of a supporting substrate film, for example, a PET film 1. The ink layer 2 whose component is a vinyl chloride / vinyl acetate copolymer is laminated, and information can be recorded on the ink layer with a laser beam having an oscillation wavelength of 700 to 1500 nm. In the processing by laser irradiation, if the beam is focused, the total output is concentrated in the same size as the wavelength at the focal point. In printing, the laser irradiation conditions are optimized while adjusting the focus to the ink layer.

A conventional paper container provided with a laser-markable film material as a front substrate can be used as a paper container using a laser-markable film material used in the present invention on the surface of the container. The paper container uses the film material capable of laser marking used in the present invention on the surface of the cover material of the paper container, the surface of the label material of the paper container, the surface of the bag body of the paper container, and the surface of the paper cup of the paper container. It is also possible.

To solve the problem of the present invention, it was performed a number of exemplary tests, and the like. For example, the selection of the ink resin system, the selection of the pigment, the optimization of the blending ratio, the optimization of the thickness of the ink layer, and the test of the layer structure among the selected resin systems were performed and evaluated. Among them, examples of the present invention and comparative examples thereof will be described below.

  In Example 1, a transparent polyester resin film 1 (PET film: general) having a thickness of 16 μm, which is a supporting substrate, was prepared.

  Next, an ink layer 2 was formed on one side of the PET film 1. Ink layer 2 is a gravure coating method using a solid gravure plate of 175 L and a depth of 30 μm, using the ink of Example 1, and is printed so that the ink coating film has a thickness of 3 μm by printing twice. .

Subsequently, the film in which the ink layer 2 was formed on one surface of the PET film 1 and the aluminum foil 4 having a thickness of 9 μm were bonded together through the adhesive layer 3. The adhesive layer 3 is a gravure coating method using a general-purpose urethane resin two-component curable adhesive solution using a solid plate of 175 L and a depth of 60 μm, and is applied so as to have a predetermined coating amount. .

Further, a low-density polyethylene layer 5 (LDPE) of an extruded polyethylene layer was bonded to the aluminum foil 4 side of the PET film 1 of the supporting substrate by an extrusion laminating method, and a hot melt layer 6 was formed on the surface of the LDPE 5. Thus, to produce a film material of the laminate used in Example 1 of a laser marking method to full Ilm material of the present invention.

In Example 2, a transparent polyester-based resin film 1 (PET film: general) having a thickness of 16 μm, which is a supporting substrate, was prepared. The ink system of Example 1 was changed and the ink of Example 2 was used. Other than that, the materials used and the manufacturing method are the same. Thus, to produce a film material of the laminate used in Example 2 of a laser marking method to full Ilm material of the present invention.

Then, a first embodiment of the laser marking method of the full Ilm material of the present invention, with respect to Example 2 was carried out in Example 3 to Example 7 as a comparative example. This will be described below.

In Example 3, a transparent polyester resin film 1 (PET film: general) having a thickness of 16 μm as a supporting substrate was prepared. The resin system in the ink of Example 1 was changed, and the ink of Example 3 was used. Other than that, the materials used and the manufacturing method are the same. Thus, to produce a film material of the laminate used in Example 3 of a laser marking method to full Ilm material of the present invention.

In Example 4, a transparent polyester resin film 1 (PET film: general) having a thickness of 16 μm as a supporting substrate was prepared. The resin system in the ink of Example 1 was changed, and the ink of Example 4 was used. Other than that, the materials used and the manufacturing method are the same. Thus, to produce a film material of the laminate used in Example 4 of the laser marking method of the full Ilm material of the present invention.

In Example 5, a transparent polyester resin film 1 (PET film: general) having a thickness of 16 μm as a supporting substrate was prepared. The pigment of Example 1 was changed to carbon black, and the ink of Example 5 was used. Other than that, the materials used and the manufacturing method are the same. Thus, to produce a film material of the laminate used in Example 5 of the laser marking method to the full Ilm material present invention.

In Example 6, a transparent polyester resin film 1 (PET film: general) having a thickness of 16 μm as a supporting substrate was prepared. The materials used and the manufacturing method are the same as in Example 1. Thus, to produce a film material of the laminate used in Example 6 of the laser marking method to full Ilm material of the present invention.

In Example 7, a transparent polyester resin film 1 (PET film: general) having a thickness of 16 μm as a supporting substrate was prepared. The materials used and the manufacturing method are the same as in Example 1. Thus, to produce a film material of the laminate used in Example 7 of the laser marking method to full Ilm material of the present invention.

  The materials used in Examples 1 to 7 of the present invention, particularly the ink layers, are shown in Table 1 below.

なお、樹脂系では、樹脂バインダーのみの固形部の重量％である。樹脂バインダーの樹脂系では、塩酢ビニル（塩化ビニル／酢酸ビニル共重合体）を主にし、ウレタン樹脂を配合し、顔料は、酸化チタンを主に実施した。

In the resin system, it is the weight percentage of the solid part of the resin binder alone. In the resin system of the resin binder, vinyl chloroacetate (vinyl chloride / vinyl acetate copolymer) was mainly used, a urethane resin was blended, and the pigment was mainly titanium oxide.

In the printing method, when laser light is irradiated on the film surface in a non-contact state, the laser light that has passed through the transparent film that is not excited is diffused by the colored pigment in the ink layer and absorbed by the ink resin around the pigment. . At this time, in the resin system of the resin binder of the ink, it is difficult to develop a color with a resin having high heat resistance, and in the resin system with poor heat resistance, gas is generated by thermal decomposition, and bleeding and bubbles are generated in and around the print. Further to improve the adhesion of an ink layer is preferably blended urethane resin in a resin binder.

  In the printing method, the pigment contained in the ink is important for efficiently diffusing laser light in the ink layer, and also for heat resistance and light reflectivity. The characteristics of the pigment are also important for visibility. When printing, it is also important to diffuse the laser beam efficiently in the ink layer, a titanium oxide-based white inorganic pigment that has good heat resistance, good light reflectivity, and good dispersibility in the ink composition. Is optimal. The white pigment is excellent in color development in the ink layer and is an optimal color.

  Next, the laminate film of the samples of Examples 1 to 7 was cut for a lid material, and after heat sealing to the top surface of a polystyrene molded cup (PS molded cup) filled with the contents, The excess part was trimmed to obtain a filled product. Next, an 8-digit number indicating the expiration date was printed on the top surface of each filled product. Next, 60 of each of the filled products of Examples 1 to 7 were encased in 12 cardboard boxes in a single stack. Laser marking was printed by the method shown in Table 2. Table 2 is shown below.

なお、試料名での配列順番では、表１と異なる配列である。マーカーは、その波長が１０００ｎｍの近傍で選択し、２種類のレーザーを主にした。

Note that the arrangement order of sample names is different from that in Table 1. The marker was selected in the vicinity of a wavelength of 1000 nm, and two types of lasers were mainly used.

  In Examples 1 to 7 of the present invention, in this case, each filled product was evaluated for printability of laser marking. In the evaluation method, first, printability was evaluated. The evaluation was visually evaluated for the superiority or inferiority of the color developability of the ink, the accuracy of printing, the bleeding, the presence or absence of bubbles, and the visual recognition of the printing. Next, the second is to perform a vibration test in accordance with JISZ-0200 for each of the filled products, 60 pieces, and visually check for the presence or absence of print peeling or rubbing on each filled product. We confirmed the number of priority products that were defective. The evaluation results are shown in Table 3 below.

なお、評価での○印は、合格レベルであり、
◎印は、合格レベル以上であり、改善レベルである。

In addition, ○ mark in evaluation is a pass level,
The mark ◎ is above the pass level and is the improvement level.

When recording information, that is, printing, non-contact printing using a laser is effective on the uneven surface. In the present invention, the laser is preferably a YAG laser or a YVO ₄ laser having a wavelength of 700 to 1500 nm. In printing, the distance between the substrate surface and the laser beam irradiation position is preferably in the range of 30 to 40 cm, the scanning speed is preferably 25 to 100 kHz, and the laser output is preferably about 1 to 10 W. In the processing by laser irradiation, if the beam is focused, the total output is concentrated in the same size as the wavelength at the focal point.

In the laser marking method to full Ilm material of the present invention is excellent can be printed, and the excellent visibility wear resistance by coloring ink layer immediately below without damaging the film substrate of the surface layer, sanitary It uses materials that have been confirmed to be suitable, has high safety, and can be widely applied to the packaging field.

FIG. 3 is a partially enlarged side sectional view for explaining an embodiment of a layer structure of a laser-markable film material used in the present invention. It is a side sectional view of a partially enlarged for explaining an embodiment of a laser marking method to full Ilm material of the present invention.

DESCRIPTION OF SYMBOLS 1 ... PET film (of support base material) 2 ... Ink layer 3 ... Adhesive layer 4 ... Aluminum foil 5 ... Extruded PE layer (LDPE)
6 ... Hot melt layer 10 ... Film material 20 capable of laser marking ... Laser irradiation light 20a ... Recording of information

Claims (7)

In a film material capable of laser marking, which is a film laminate that records information using laser light, the component contained in the resin binder is a vinyl chloride / vinyl acetate copolymer on one side of the support base film. A film laminate in which an ink layer is laminated, wherein the vinyl chloride / vinyl acetate copolymer contained in the resin binder contains 60% by weight or more, and the main pigment component contained in the ink layer is titanium oxide. With respect to a film material capable of laser marking having a pigment content of 30% by weight or more of the solid content of the ink, a YGA laser or a YVO ₄ laser is used for the ink layer with a laser beam having an oscillation wavelength of 1064 nm. laser marking method to full Ilm material you and performs recording of information. The substrate film is a transparent plastic film, laser marking method of the claim 1 Symbol placement of full Ilm material, characterized in that the aluminum foil is laminated through an adhesive ink layer laminated side. In the paper container which arranged the film material which can be laser-marked as a surface base material, the film material which can be laser-marked by the laser marking method to the film material of the said Claim 1 or 2 is arrange | positioned on the container surface, Information is obtained by this method. A method of laser marking on a paper container , characterized in that recording is performed . Laser markable film material placed in the lid surface of the paper container by laser marking method of the claim 1 or 2, wherein the film material, according to claim 3, wherein the recording information by the method Laser marking method for paper containers. Laser markable film material placed on the label material surface of the paper container by laser marking method to claim 1 or 2, wherein the film material, according to claim 3, wherein the recording information by the method Laser marking method for paper containers. Laser markable film material placed in the bag surface of the paper container by laser marking method to claim 1 or 2, wherein the film material, according to claim 3, wherein the recording information by the method Laser marking method for paper containers. 4. The paper according to claim 3, wherein a film material that can be laser-marked by the laser marking method for a film material according to claim 1 or 2 is disposed on a paper cup surface of a paper container, and information is recorded by the method. Laser marking method on containers.

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