JP2011148094A - Method for laser-marking laminate for lid, laminate for distribution package lid and distribution package with marking - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distribution package which is not exposed out of an outer surface of a distribution packaging bag, in which printed letters of a commodity name, a manufacturer symbol, a manufacture date or the like are not erased by external friction and which does not comes into direct contact with foods or the like as a packaged matter and further which facilitates reading. <P>SOLUTION: The distribution package has a hard lid body which has a folding line having a half cut section formed from a surface side at a surface center part and a protrusion forming a discharge port when bent and a flexible container body which has a pocket for housing contents and a peripheral part of the flexible container body is welded to a rear surface of the hard lid body. The hard lid body is a hard composite laminate formed by laminating at least a surface layer, a hard intermediate layer and a seal layer at a rear surface of the hard lid body. The laminate and the distribution package are subjected to laser marking where a resin colored by pigment in the hard intermediate layer is turned black by carbonization caused by irradiation with laser beams and in this laser marking method, a font where a place of carbonization blackening is not irradiated again with laser beams is used. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a laser marking method for a laminate to be marked by laser printing, a laminate for a distribution package lid, and a distribution package marked by laser printing.

Conventional markings on the distribution package include those printed on the surface of the distribution package, such as a jet printer, when the date and other manufacturer symbols are printed individually. On the other hand, in recent years, laser printing has been used as a marking method that does not use ink, such as a printing method that exposes the background (Patent Document 1), or a printing method that eliminates the ink layer of a packaging film locally (Patent Document 2). A method of forming a marking portion by removing a designated portion of a colored layer by light irradiation is performed.

JP 2008-155471 A JP 2007-38594 A

The problem to be solved by the present invention is that, in the conventional laser marking, paint or ink is interposed, and the surface irradiated with the laser light is burnt with the painted surface removed, so the surface becomes rugged . In addition, when laser marking is performed on a layer using laser receiving ink for printing on the back surface of the surface layer, there has been a problem that the film in the printed portion is slightly lifted due to foaming or gasification of the ink disappearing. Therefore, it is not exposed on the outer surface of the distribution packaging bag, the product name, manufacturer symbol, date of manufacture, etc. are not lost due to external friction, and directly as food to be packaged. In addition, it is possible to realize a display that can be read easily and reliably without contact. That is, a method of printing a product name, date, manufacturer's symbol, etc. by laser light on a resin layer on the inner surface of the laminate without changing the outer surface of the product, a laminate for a distribution package lid, and a marked distribution package Is to provide a body.

The laser marking method for the lid laminate according to the present invention is a laser marking method in which at least a surface layer, an intermediate layer, and a seal layer are laminated to irradiate a laser beam to carbonize the resin in the intermediate layer. 1 is characterized in that a font is used in which the laser beam is not re-irradiated to the blackened portion.

Moreover, in the laminated body for distribution packaging body lids, a hard lid body having a fold line having a half-cut portion formed from the surface side at the center portion of the surface and a convex portion forming a discharge port when folded. And a distribution packaging body having a flexible container body having a pocket portion for containing contents, wherein the peripheral edge portion of the flexible container body is welded to the back surface of the hard lid body, the hard lid body Is a hard composite laminate formed by laminating at least a surface layer, a hard intermediate layer, and a seal layer, and the resin in which the hard intermediate layer is colored with a pigment is laser-printed and the laser beam is re-irradiated to the blackened portion It is characterized by being a laminated body that is marked using a non-printing font.

Moreover, the hard intermediate layer may be a PS resin layer, and the color pigment may be titanium dioxide.

These markings can be made by carbonizing the resin using a laser beam and turning it black. However, if the base is white, the contrast with the blackening portion is large and can be clearly displayed. Titanium dioxide is used as the white pigment, and when the portion once blackened is irradiated again with laser light, carbonization is accelerated at once, gas is generated, and cavities are generated in the laminated section. Therefore, it is important to use a special font that does not irradiate the same place with laser light.

Further, the marked distribution package according to the present invention has a fold line having a half-cut portion formed from the surface side at the center of the surface and a hard lid having a convex portion that forms a discharge port when folded. A distribution lid having a flexible container body having a body and a pocket portion for containing contents, wherein the peripheral edge of the flexible container body is welded to the back surface of the rigid lid body. Is composed of at least a surface layer, a hard intermediate layer, and a seal layer. The hard intermediate layer is a PS resin, the PS resin is a mixture of GPPS and HIPS, contains titanium dioxide as a pigment, and the laser beam is blackened. It is characterized by marking with a font that does not re-irradiate the part.

Further, a liquid container or a paste-like material is filled in a flexible container body in a pocket portion for storing contents on the back surface of the sealing layer of the hard lid, and laser printing is performed from the surface layer side of the hard lid. The above-mentioned problem is solved by providing a distribution package marked with the above.

According to the method according to the present invention, the distribution package lid laminate, and the marked distribution package, the laser beam is transmitted through the surface layer and the surface of the hard white intermediate layer is changed to black. Black markings can be made, and markings such as product names, dates, and manufacturer symbols can be clearly recognized as black characters on a white background through the surface layer. This ensures that the product name, manufacturer's symbol, date of manufacture, etc. are not lost due to external friction, and that the marking does not come into direct contact with foods, etc. as packaged items. By making the display easy and reliable, it is possible to solve problems such as in-packing of food such as prevention of tampering and adhesion of marking ink in addition to appearance.

It is explanatory drawing which shows the typical structure of the laminated body for distribution packaging body lid | covers of one Example which concerns on this invention. It is explanatory drawing which shows the typical structure of the laminated body for distribution packaging body lid | covers of one Example which concerns on this invention. It is explanatory drawing explaining the marking font used for one Example of this invention. It is explanatory drawing which shows the marked distribution package of one Example of this invention.

The present invention will be described below with reference to the drawings.
In FIG. 1 and FIG. 2, representative examples of examples of the laminated body of the distribution package are described.
In other words, the hard lid according to one embodiment of the present invention includes at least a surface layer, an intermediate layer, and a seal layer.
Furthermore, a barrier layer can be provided between the intermediate layer and the seal layer and between the surface layer and the intermediate layer.

Surface layer is amorphous unstretched PET (APET), stretched PET (OPET), crystalline PET (CPET), stretched PP (OPP), unstretched PP (CPP), polybutylene terephthalate (PBT), stretched Ny (ONy) ), Unstretched Ny (CNy), polyethylene naphthalate (PEN), stretched PS (OPS), and the like.

The intermediate layer is required to have a brittle fracture in which a convex portion is opened to form a discharge port when the half cut portion formed from the surface side of the hard lid is bent along a fold line. In order to moderate plastic deformation and brittle fracture, a polystyrene-based resin (hereinafter sometimes referred to as “PS resin”) is selected for the intermediate layer, and as a constituent polystyrene-based resin, good cracking properties are obtained. From the viewpoint of obtaining good adhesion to the sealing layer or the barrier layer, general-purpose polystyrene (hereinafter sometimes abbreviated as “GPPS”), impact-resistant polystyrene (hereinafter referred to as “HIPS”). Or a single resin of styrene / butadiene block copolymer (butadiene-based compound) or a mixture of these resins. Since GPPS does not contain a rubber component, it has a property of being easily broken.

On the other hand, HIPS includes a rubber component and has a property of being hard to break. Therefore, by appropriately adjusting these mixing ratios, it is possible to adjust the crackability of the hard lid material when the discharge port of the package is opened. When a mixture of GPPS and HIPS is used as the polystyrene-based resin constituting the intermediate layer, HIPS, based on the total mass of the PS layer (100% by mass),
It is preferably 3 to 20% by mass, and more preferably 5 to 10% by mass. As GPPS, a heat-resistant grade having a flexural modulus of 3,200 to 3,300 MPa and a Charpy impact strength (notched) of 1.5 to 3.0 KJ / m 2 is preferably used. As HIPS, a high impact grade having a flexural modulus of 2,100 to 2,500 MPa and a Charpy impact strength (notched) of 13 to 16 KJ / m 2 is preferably used. As the styrene / butadiene block copolymer, Asaflex, Tuffprene, Asaprene manufactured by Asahi Kasei Corporation can be suitably used.

The melt flow rate of the polystyrene resin is preferably 1 g / 10 min [200 ° C. 5 Kg] or more, and more preferably 4 g / 10 min [200 ° C. 5 Kg] or more.
The flexural modulus (JIS K7171) of the polystyrene resin constituting the PS layer is preferably 1700 MPa to 2800 MPa, more preferably 2000 MPa to 2500 MPa. The Vicat softening temperature (JIS K7206) is preferably 75 to 110 ° C, more preferably 80 to 100 ° C.

  The thickness of the intermediate layer is preferably 50 to 550 μm, more preferably 200 to 450 μm, and particularly preferably 200 to 350 μm. If the thickness of the intermediate layer is too thin, it will be difficult to obtain good openability when used as a distribution package. On the other hand, when the thickness of the intermediate layer is too thick, it is difficult to open easily, and the commercial value as a distribution package is lowered.

In addition, it is important that the intermediate layer contains a titanium dioxide pigment in the resin layer for the purpose of enhancing the sharpness of the marking output by the laser beam. This is done in a plastic matrix by mixing titanium dioxide with plastic granules and shaping under the action of heat. Such doped plastic granules are usually produced by introducing the plastic granules into a suitable mixer, moistening them with conventional additives, and then adding and mixing titanium dioxide.

Plastics are usually colored with color concentrates (masterbatches) or compounds. The resulting mixture can then be processed directly in an extruder or injection molding machine.
Titanium dioxide is substantially insoluble in the dispersion medium (preferably water) and is ground to an individual average particle size of about 1 micron to about 10 microns, preferably about 1 to 3 microns.
In this way, the titanium dioxide pigment can be distributed homogeneously in the plastic. An intermediate layer made of a resin composition having a titanium dioxide content of 0.01% to 50.0% by weight based on the resin can be obtained.

When blending a pigment such as titanium dioxide in the intermediate layer, various additives are added to improve the dispersibility and processing suitability of the pigment. Generally, metal soap is used as a lubricant. . The metal other than zinc, lithium and calcium used in the present invention is not particularly limited as long as the effects of the present invention are not impaired, and magnesium, aluminum, and the like can be used.

The seal layer is a layer composed of any of low density polyethylene (LDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), or a mixture thereof.
For example, the blending ratio of LDPE and HDPE can be freely controlled to adjust the cracking property of the lid material when opening the package and the adhesive strength with the intermediate layer. Moreover, the tearability of a polyethylene-type resin layer can be prepared with both compounding ratios. The higher the HDPE ratio, the better the tearability. Moreover, by increasing the blending of LDPE, the melt tension can be increased and the film-forming property can be stabilized.

  The LDPE preferably has a density of 0.92 g / cm 3 or more, and the HDPE preferably has a density of 0.95 g / cm 3 or more. By increasing the density, it is possible to impart good tearability to the PE layer. The linear low density polyethylene LLDPE preferably has a density in the range of 0.91 to 0.94 g / cm 3 and a melt flow rate of 0.5 to 15 g / 10 min.

 Further, the sealing layer may have a multilayer structure of a PE first layer and a PE second layer. For the PE layer having such a two-layer structure, LDPE, HDPE, or a blend of LDPE and HDPE is used. In determining the blend ratio, the following considerations should be made while considering the layer thickness. That is, it is preferable that the PEPE layer forming the outermost layer of the sealing layer has a high LDPE blending ratio in order to ensure sealing performance and appropriate opening performance. On the other hand, the PE second layer on the intermediate layer side needs to propagate the “cut” of the layer (film) well with the crack of the PS layer as the main constituent layer. It is also preferable. The blending ratio of LDPE and HDPE is 40-80: 60-20, preferably 50-80: 50-20, more preferably 60-80: 40-20 by mass ratio. Depending on the blending ratio of LDPE and HDPE, the melt tension is increased by LDPE to stabilize the film forming property, and the lid material is excellent in the property of being easily cracked when opened with HDPE (hereinafter referred to as “easy cracking”). Can be obtained.

  The thickness of the PE second layer 19 of the seal layer 12 is preferably 2 to 70 μm. More preferably, it is 3-20 micrometers, Most preferably, it is 5-10 micrometers. By keeping the thickness of the PE second layer of the sealing layer in the above range, it becomes possible to keep the PE layer at the time of opening well. Moreover, it is preferable that the thickness of PE 1st layer which comprises a sealing layer is 2-70 micrometers. More preferably, it is 3-20 micrometers, Most preferably, it is 5-10 micrometers. By defining the thickness of each PE layer in this manner, it becomes possible to maintain good sealing properties while maintaining good cutting at the time of opening.

As the barrier layer, an EVOH layer can be provided between the intermediate layer and the seal layer, or between the surface layer and the intermediate layer. The EVOH layer functions as an oxygen barrier layer and can impart gas barrier properties to the film. EVOH has an ethylene content of 29 mol% or more, preferably 32 mol% or more, and is 47 mol% or less, preferably 44 mol% or less. The saponification degree of EVOH is preferably 90 mol% or more, more preferably 95 mol% or more.
The thickness of the EVOH layer between the intermediate layer and the seal layer is 2 μm or more, preferably 5 μm or more, and 15 μm or less, preferably 10 μm or less. If the EVOH layer is too thin, it is difficult to maintain good oxygen barrier properties. On the other hand, the thickness of the EVOH layer is not preferable because it obstructs the opening of the discharge port of the package.

On the other hand, the thickness of the EVOH layer between the surface layer and the intermediate layer can be set to 15 μm or more, preferably 30 μm or more. Although the hard lid is bent along the fold line portion by bending a fold line having a half cut portion from the surface layer side to the intermediate layer, a crack can be formed on a straight line to form a discharge port. Since the EVOH layer has been cut by half-cutting, its thickness can be freely set as compared with the case where it is disposed on the seal layer side, but the upper limit is substantially about 50 μm.

The surface layer, the intermediate layer, the seal layer, and each laminate can be made into a laminate by coextrusion or dry lamination, and a resin and configuration suitable for the contents to be filled in the distribution package can be selected.

Printing on the hard lid can be performed using a general printing method such as offset printing, gravure printing, or screen printing on the front surface or the back surface. However, the laser marking portion has a color tone that can be clearly recognized by overcoat printing or laser printing, and can perform printing of colors that transmit laser light and are not involved in laser light.
In front printing, there is no possibility that the printing surface will be damaged due to friction, but printing can be performed on a prepared laminate film. On the other hand, the problem of printing blur can be solved by performing back printing and dry laminating to the intermediate layer side. However, it is necessary to prepare a printing film and a base film, and a printing method and a printing method can be selected depending on the lot of the laminated body of the hard lid material and the intended use.

  In general, lasers used for laser processing are roughly classified into two types depending on the oscillation wavelength. The first is that the oscillation wavelength is in the vicinity of 1064 nm, and the object that can be printed or the like differs depending on the medium and method for amplifying the light. This laser with an oscillation wavelength of 1064 nm is good in processing of resin and metal, but cannot process a transparent object. Typical examples of this type of laser include YAG (yttrium, aluminum, garnet) laser, YVO4 laser, and FAYb laser. YAG lasers are capable of metal engraving and are also available with low wavelengths. The YVO4 laser can print on metal and is suitable for fine marking. In addition, the FAYb laser has a feature that it is advantageous in printing by shortening the pulse width depending on the model to reduce the thermal effect.

  The second is that the oscillation wavelength is in the vicinity of 10600 nm, and the laser having the oscillation wavelength of 10600 nm can print on paper or a transparent object. A typical example of this type of laser is a CO2 laser. The CO2 laser has a feature that it can process a resin and a transparent object, but cannot process a metal.

It is preferable to irradiate the laminated body for a distribution package lid with a YVO4 laser beam having a wavelength in the near infrared region of 1064 nm. This YVO4 laser beam enables fine marking such as small characters and processing, and is excellent in high-speed printability. In particular, the single mode beam has a perfect circular light beam and enables particleless printing, as well as excellent laser power stability and uniform printing, so laser power, scan speed, By adjusting the printing pulse cycle, the color of the resin can be adjusted. In addition, when using a carbon dioxide laser or the like, if the laser light irradiation on the laminated plastic film is too strong, it is difficult to check with the naked eye, but only the character part on the film surface is slightly torn, There may be scratches.

In this respect, the YVO4 laser can finely adjust the power, so that the surface of the intermediate layer to which titanium dioxide is added as a pigment is transmitted through the substantially transparent surface layer, or the surface layer and the barrier layer, and coloring is caused by carbonization. Characters can be printed. Further, the marking by carbonization has a large contrast with the white background, and can be clearly displayed. However, if laser light is irradiated again to the part once turned black, carbonization is accelerated at once, and gas is generated and cavities are generated in the cross section of the surface layer and the intermediate layer. In combination, it is necessary to devise a method that does not irradiate the same place with laser light.

The structure of the laminated body of the hard lid used in the examples was a structure of PET // PS / titanium oxide pigment-containing HIPS / PS / adhesive PE / EVOH / adhesive PE / PE from the surface layer side, and the total thickness was 350 μm. It was.
Moreover, the thickness of PET and PS from the surface layer to the titanium oxide pigment-containing HIPS was 50 to 60 μm.
Laser equipment SUNX LP-Z256
Character size: Height 3mm Width 2.5mm
Distance between workpieces: 310mm
Output setting: 30-45%
Scan speed: 1200mm / s
Marking area: 300mm x 300mm
Marking content: Expiration date, product abbreviation

The composition of the laminate of the hard lid used in the examples is the composition of PET // EVOH // PS / titanium oxide pigment-containing HIPS / PS / adhesive PE / EVOH / adhesive PE / PE from the surface side. It was 380 μm.
Moreover, the thickness of PET, EVOH, and PS from the surface layer to the titanium oxide pigment-containing HIPS was 80 to 100 μm.
Laser equipment SUNX LP-Z256
Character size: Height 3mm Width 2.5mm
Distance between workpieces: 310mm
Output setting: 30-45%
Scanning speed: 1000mm / s
Marking area: 150mm x 300mm
Marking content: Expiration date, product abbreviation

A font in which the laser beam does not re-irradiate the blackened portion will be described based on an example of FIG.
For the sake of explanation, the miracle of laser irradiation is shown in white as an example of the numbers 1 to 4 and the letters ml, DPJ, and + indicating a cross part. Prints irradiated with laser light are unexposed characters. The example of the location 21 which avoids the part which a laser beam overlaps with D, 4 and + was shown.
To explain further, the number “3” shortens the writing position of the lower “t” in order to eliminate the overlapping of the upper “t” and the lower “t”. The number “0” has no writing and no writing end, and since it is continuous, the writing position and the writing end position overlap each other, so that it is emphasized or foamed. Therefore, the problem is solved by slightly separating the writing position and the writing end position.
Similarly, the alphabet “m” can be solved by shortening the writing of “l”, “tsu”, and “tsu” and eliminating the overlap.
Similarly, when crossing like “+”, one side is cut and separated. In other words, the overlap can be eliminated by separating into “l” and “−” and “−”.
Other characters, numbers, and symbols can be combined to create a font that prevents overlap and overlap, thereby preventing gas generation and emphasis and providing good-looking (character) marking. These fonts can be handled by storing them in a marking device.

1 Hard lid 11 Surface layer 12 Surface layer printing position (back side printing)
13 (Hard) Intermediate layer (PS layer)
14 Barrier layer (EVOH layer)
15 Sealing layer 16 Coloring by laser beam (schematic diagram)
2 Pocket 3 Packaging 5 Marking (date, symbol)
6 Convex 7 Folding line (half cut)
9 Hard lid 20 Marking font (example)
21 Locations where laser light overlap is prevented (example)

Claims (5)

In a laser marking method in which at least a surface layer, an intermediate layer, and a seal layer are laminated, and laser beam is irradiated to change the resin of the intermediate layer to carbonize black, a font that does not re-irradiate the laser beam blackened portion with a laser beam A laser marking method for a laminated body for a lid, characterized by being used. A hard lid having a fold line having a half-cut portion formed from the surface side at the center portion of the surface and a convex portion forming a discharge port when folded, and a pocket portion for accommodating contents In a distribution package having a flexible container body and a peripheral edge of the flexible container body welded to the back surface of the hard lid body, the hard lid body includes at least a surface layer, a hard intermediate layer, and a seal layer. A hard composite laminate formed by laminating a resin in which the hard intermediate layer is colored with a pigment, and marking is performed using a font in which laser light is not re-irradiated to a carbon blackening spot. The laminated body for distribution packaging body lid characterized by this. The distribution package body lid laminate according to claim 2, wherein the hard intermediate layer is a PS resin layer and the color pigment is titanium dioxide. A hard lid having a fold line having a half-cut portion formed from the surface side at the center portion of the surface and a convex portion forming a discharge port when folded, and a pocket portion for accommodating contents In a distribution package having a flexible container body and the peripheral edge of the flexible container body welded to the back surface of the hard lid body, the hard lid body is composed of at least a surface layer, a hard intermediate layer, and a seal layer. The hard intermediate layer is PS resin, the PS resin is a mixture of GPPS and HIPS, contains titanium dioxide as a pigment, and is marked with a font that does not re-irradiate the carbon blackening spot. Marked distribution package characterized by. Marking by laser printing from the surface layer side of the hard lid, in which the flexible container body of the pocket portion for containing the contents is filled on the back surface of the seal layer of the hard lid body, and the liquid or paste-like material is filled 5. A marked distribution package according to claim 4.

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