JP2010076180A - Laminated film and packaging film using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated film, capable of being clearly marked, and providing a printed image with good contrast after printing which is never externally affected and can be prevented from alteration, forgery, or the like. <P>SOLUTION: The laminated resin film includes: a laser color development layer which develops color under laser irradiation; a surface layer provided on the laser-irradiated side of the laser color development layer; and a colored layer provided on the opposite side to the laser-irradiated side. The laser color development layer includes a thermoplastic resin containing a laser color former. The content of the laser color former to the thermoplastic resin is 5-50 wt.%, and the total thickness of the laminated film is 8-120 μm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laminated film, and more specifically, is a laminated film that absorbs its energy by laser beam irradiation and develops a color by vivid color and has a good contrast of a printed image after printing. In addition, the present invention relates to a laminated film in which a printed image is not affected externally and can be prevented from being altered or counterfeited.

  Conventionally, the manufacturer's name, product name, date of manufacture, expiration date, other indications, etc. are printed on the surface of packaging materials, industrial members, card members, label members, business form members, and other plastic molded product members. As one of the methods, a marking method by laser beam irradiation (laser marking) is known.

  For example, a method of printing by irradiating a carbon dioxide laser beam onto the surface of a molded product made of a resin composition containing no metal powder containing 0.05 to 0.5 parts by weight of titanium oxide-coated mica in a polyolefin resin. No. 3-48872: Patent Document 1), a polyolefin resin composition for laser marking containing 0.005 to 0.5% by weight of a silicon compound with respect to the polyolefin resin (Japanese Patent Laid-Open No. 7-286074: Patent Document) 2) and the use of a thermoplastic plastic containing a pigment having a tin dioxide coating as a laser markable plastic (Japanese Patent Publication No. 10-500149: Patent Document 3, etc.) is known.

  The laser marking resin and the printing method proposed in the above-mentioned patent document form a laser print image directly on the surface of a plastic molded article, etc., so that the print image can be obtained by rubbing the surface of the laser print image. Is erased, so that there is a problem that the modification or forgery can be easily performed. In addition, when laser marking resin is used as a film, pinholes (small holes) may be opened in the film by the heat of laser light during printing, and laser marking resin is used for molded products. Even in this case, irregularities were formed on the surface of the molded body irradiated with the laser, and there was a case where an accident occurred in which the molded body was damaged around this portion.

  Due to such a problem, for example, in Japanese Patent Application Laid-Open No. 2004-268554 (Patent Document 4), Japanese Patent Application Laid-Open No. 2005-144784 (Patent Document 5), and Japanese Patent Application Laid-Open No. 2002-273732 (Patent Document 6), color is generated by irradiation with laser light. It has been proposed that a multilayer structure in which a resin layer is provided on one or both sides of a layer can prevent modification, forgery, and the like, and can prevent occurrence of pinholes and irregularities.

  Japanese Patent Laid-Open No. 2006-213090 (Patent Document 7) provides a colored layer on a side opposite to the laser printing side of a coloring layer containing a predetermined amount of a laser coloring agent in a molded article such as a laser-markable card. It has been proposed to improve the visibility by increasing the contrast with the printed image.

Japanese Examined Patent Publication No. 3-48872 Japanese Patent Laid-Open No. 7-286074 Japanese National Patent Publication No. 10-500149 JP 2004-268554 A JP 2005-144784 A JP 2002-273732 A Japanese Patent Laid-Open No. 2006-213090

  However, the laser marking resin film proposed in the above patent document has insufficient contrast between the printed image and the surroundings in the relationship between the color printed by the laser light irradiation and the color of the member constituting the laminated film. There are cases. In addition, when the laminated film is used in applications such as a package or a molded container, it may be assumed that the visibility of a laser-printed print image is inferior depending on the color of the content to be filled. Furthermore, depending on the relationship between the color of the surface on which the printed image of the laminated film is observed and the color of the opposite surface, the contrast between the printed image and the surrounding area is low, and visibility may be lacking.

  When the inventors have applied the technical knowledge proposed in the above cited document 7 to film use, it has been found that a printed image with good contrast cannot be obtained. And because the reason is that the sufficiently thick form like a sheet molded product and the thin form like a film have a different pigment content even at the same concentration, good printing is possible. In the multilayer film, especially the multilayer film formed by coextrusion, by adding a predetermined amount of a laser color former, a clear laser marking is possible. It was found that a printed film after printing has good contrast, and the printed image is not affected externally, and a laminated film that can prevent modification, forgery, and the like can be obtained. The present invention is based on such knowledge.

  Therefore, the object of the present invention is that clear laser marking is possible, the printed image after printing is good in contrast, the printed image is not affected externally, and its alteration, forgery, etc. can be prevented. It is to provide a laminated film.

  The laminated film according to the present invention comprises a laser color layer that develops color by laser light irradiation, a surface layer provided on the laser color irradiation side of the laser color layer, and a side opposite to the laser light irradiation side. A layered film comprising at least a colored layer provided, wherein the laser color-developing layer is made of a thermoplastic resin containing a laser color-developing agent, and the laser color-developing agent is in contact with the thermoplastic resin. 5 to 50% by weight is included, and the total thickness of the laminated film is 8 to 120 μm.

  According to the aspect of the present invention, it is preferable that the thickness of the laser coloring layer is 1 to 50 μm.

  Moreover, according to the aspect of this invention, it is preferable that the thickness of the said colored layer is 1-50 micrometers.

  Moreover, according to the aspect of this invention, it is preferable that the thickness of the said surface layer is 1-100 micrometers.

  Furthermore, according to the aspect of the present invention, it is preferable that the ratio of the thickness of the laser coloring layer and the thickness of the colored layer is 1: 4 to 15: 1.

  Moreover, according to the aspect of the present invention, it is preferable that the laminated film is formed by coextrusion molding.

  Furthermore, according to the aspect of the present invention, the surface layer is preferably made of a transparent thermoplastic resin.

  According to the aspect of the present invention, it is preferable that a heat seal layer is provided on the side of the colored layer opposite to the laser coloring layer side.

  In another aspect of the present invention, a packaging material using the above laminated film is also provided.

  The laminated film according to the present invention is a laminated film composed of a surface layer, a laser coloring layer and a colored layer and having a total thickness of 8 to 120 μm, and contains 5 to 50% by weight of a laser coloring agent in the laser coloring layer. Therefore, even when printing is performed on a laminated film by laser beam irradiation, a clear print image can be formed and a print image with good contrast can be obtained. Further, since the surface layer is provided, the printed image is not affected externally, and its alteration, forgery, etc. can be prevented.

  The laminated film according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of a laminated film according to the present invention. The laminated film according to the present invention comprises a laser coloring layer 2 that develops color by laser light irradiation, a surface layer 1 provided on the laser color irradiation side of the laser coloring layer, and a side opposite to the laser light irradiation side. And at least the colored layer 3 provided. And the total thickness of a laminated | multilayer film is the range of 8-120 micrometers, Preferably it is about 40-60 micrometers.

  In the present invention, as shown in FIG. 2, a heat seal layer 4 is preferably provided on the side of the colored layer 3 opposite to the laser coloring layer 2 side. By providing a heat seal layer, as will be described later, when the laminated film according to the present invention is used as a packaging material, a package can be easily formed by heat sealing. Further, a base film may be bonded to the surface layer 1 side by a method such as dry lamination or extrusion lamination. In addition, in this invention, it is good also as a laminated | multilayer film which consists of another form by laminating | stacking another base material arbitrarily according to the use purpose, a use, etc. further. Hereinafter, each layer which comprises the laminated | multilayer film of this invention is demonstrated.

<Surface layer>
The surface layer constituting the laminated film of the present invention mainly serves to protect the printed image laser-marked on the laser coloring layer. Therefore, it is necessary to be formed of a material that can transmit laser light, and it is also necessary to be able to clearly see the printed image laser-marked on the laser coloring layer. For these reasons, it is preferable to use a transparent or translucent thermoplastic resin for the surface layer, and it is more preferable to use a transparent thermoplastic resin.

Furthermore, in the present invention, as will be described later, since the multilayer film is preferably produced by a coextrusion film forming method, it can be melted by heat and extruded from an extrusion die such as an extruder. It is preferable that the layer can be thermally fused to each other. Such a thermoplastic resin is not particularly limited. For example, low-density polyethylene (LDPE), linear (linear) low-density polyethylene (a polymer polymerized using a multisite catalyst, LLDPE). ), Ethylene-α-olefin copolymer polymerized using metallocene catalyst (single site catalyst), medium density polyethylene (MDPE), high density polyethylene (HDPE), polypropylene resin, ethylene-vinyl acetate copolymer, ionomer resin , Ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, methylpentene polymer, polybutene polymer, polyethylene Or polypropylene such as polypropylene Acid-modified polyolefin resins, polyvinyl acetate resins, poly (meth) acrylic resins obtained by modifying vinyl resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid One or more thermoplastic resins such as a polyvinyl chloride resin, a polystyrene resin, a polycarbonate resin, a thermoplastic polyester resin, and a thermoplastic polyamide resin can be used.
If necessary, for example, film processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness, mold release properties, flame retardancy, antifungal properties, electrical properties, For the purpose of improving and modifying strength, etc., one or two or more of various plastic compounding agents and additives are arbitrarily added, and if necessary, a solvent, a diluent, etc. are added and kneaded sufficiently. Thus, the resin composition can be adjusted.

  The surface layer preferably has a thickness of 1 to 50 μm, more preferably 5 to 20 μm. The film thickness of the surface layer is less than 1 μm, from the viewpoint of surface protection functionality and appearance, and further from the viewpoint of coextrusion stability, etc., and when the film thickness exceeds 50 μm, It is not preferable from the viewpoint of increasing the cost.

<Laser coloring layer>
The laser coloring layer is made of a thermoplastic resin containing a laser color former. As the thermoplastic resin, the same ones as described above can be used. However, the thermoplastic resin can be melted by heat and extruded from an extrusion die such as an extruder, and further thermally fused with other layers. It is preferable that it is possible.

  As the color former that develops color by laser light irradiation, conventionally known ones, for example, colorants such as dyes and pigments, clays and the like can be used. Specifically, yellow iron oxide, inorganic lead compounds, manganese Metallic compounds such as violet, cobalt violet, mercury, cobalt, copper, bismuth, nickel, pearlescent pigments, silicon compounds, mica, kaolins, silica sand, diatomaceous earth, talc, titanium oxide coated mica, tin dioxide coated mica , Antimony-coated mica, tin + antimony-coated mica, tin + antimony + titanium oxide-coated mica, and the like can be used.

  The laser color former is contained in the range of 5 to 50% by weight with respect to the thermoplastic resin. In this invention, it is preferable to contain 5 to 20 weight%. If it is less than 5% by weight, it is not preferable because the coloring, printing is inadequate or unclear, and the coloring of the printing becomes deeper as the amount of added pigment increases, but if it exceeds 50% by weight, the cost increases. In addition, the strength of the co-extruded multilayer laminated resin film is not preferable, and the pigment color of the color former itself that develops color by laser beam irradiation is not preferable.

  The laser coloring layer preferably has a thickness of 1 to 50 μm, more preferably about 5 to 20 μm. When the film thickness is less than 1 μm, color development or printing by a color former that develops color by laser beam irradiation may be insufficient or unclear. On the other hand, as the film thickness increases, the color of the print becomes deeper. However, if the film thickness exceeds 50 μm, the color development and printing by the color former that develops the color by laser beam irradiation is sufficient, but the cost increases, and the coextruded laminated film The pigment color of the color former itself, which develops color by irradiation with a laser beam, is not preferable due to reasons such as coloring the laminated film. When the amount of pigment used is the same, the visibility of printing is slightly improved when the additive concentration is higher and the film thickness is thinner.

<Colored layer>
The colored layer constituting the laminated film according to the present invention is provided for the purpose of improving the visibility of a printed image when a printed image is formed on the laser coloring layer by laser marking. When using a multilayer film as a packaging container, if the colored layer is not provided, the color of the contents can be visually recognized when the packaging container is filled with contents of a color different from the laser-marked printed image. Depending on the degree of transparency, the degree of illumination, the visibility of the printed image may be reduced. In particular, when the color of the content is the same as the color of the printed image, the visibility of the printed image is significantly reduced. In the present invention, by providing a colored layer, it is possible to arrange a color with a significantly different contrast around the laser-marked printed image, and further to shield the back of the image, so that the color and transparency of the contents Regardless of the lighting condition, the visibility of the printed image can be always secured.

  As the colored layer, a thermoplastic resin obtained by adding a colorant can be suitably used. As the thermoplastic resin, the same ones as described above can be used. However, the thermoplastic resin can be melted by heat and extruded from an extrusion die such as an extruder, and further thermally fused with other layers. It is preferable that it is possible.

  The colorant can be printed depending on the color of the laser coloring layer itself, the color that develops when irradiated with laser light, the contents of the multilayer film used when the multilayer film is used as a packaging material, the color of the laminate member used when the packaging material is used, etc. The color of the color and the type of the pigment are arbitrarily selected so that can be clearly seen. For example, when the laser coloring layer is highly transparent gray, the color developed by laser marking is black, and the content is black, high visibility can be obtained by selecting a white colorant.

  Examples of white colorants include basic lead carbonate, basic lead sulfate, basic lead silicate, zinc white, zinc sulfide, lithopone, antimony trioxide, anatase-type titanium oxide, rutile-type titanium oxide, calcium carbonate, One type or two or more types of white pigments such as zinc oxide and barium sulfate can be used.

  As the black colorant, for example, one or more kinds of black pigments such as iron black, graphite, carbon black, and electrically conductive materials (polyaniline, polypyrrole) can be used.

  The amount of the colorant used is 0.1 to 60% by weight, preferably about 5 to 20% by weight, based on the thermoplastic resin. If the added amount of the colorant is less than 0.1% by weight, the color density is low, and the effect of improving the visibility of the printed image may be insufficient. Therefore, it is necessary to determine the practical density. On the other hand, as the amount of the added colorant increases, the color of the print becomes deeper. However, if the amount exceeds 60% by weight, it is not preferable for reasons such as an increase in cost and a decrease in strength of the laminated film.

  The colored layer preferably has a thickness of 1 to 50 μm, more preferably 5 to 20 μm. When the film thickness is less than 1 μm, the coloring becomes insufficient and the visibility becomes insufficient. On the other hand, as the film thickness increases, the color of the print becomes darker and the visibility is improved. However, if the film thickness exceeds 50 μm, it is not preferable for reasons such as increased cost and reduced strength of the laminated film. In addition, when the content of the colorant with respect to the entire colored layer is the same amount, the concentration of coloring and the visibility of printing are improved by decreasing the addition concentration and increasing the film thickness.

<Heat seal layer>
In the laminated film according to the present invention, a heat seal layer may be provided on the side of the colored layer opposite to the laser coloring layer side. When the laminated film of the present invention is used for a packaging material as described later, a heat seal layer is provided so that it can be easily sealed to form a bag. A conventionally well-known thermoplastic resin can be used for a heat seal layer, for example, it can form using the above-mentioned thermoplastic resins. According to the present invention, it is preferable to form the heat seal layer using the same kind of thermoplastic resin as the surface layer.

  The heat seal layer preferably has a thickness of 1 to 100 μm, more preferably 15 to 40 μm. If the film thickness is less than 1 μm, it is not preferable from the viewpoint of surface protection functionality, layer stability at the time of sealing, and from the viewpoint of stability at the time of coextrusion film formation as described later, and the film thickness is 100 μm. Exceeding the cost increases the cost.

<Method for producing laminated film>
The multilayer film according to the present invention can be preferably manufactured by a coextrusion film forming method. Examples of the coextrusion film forming method include known methods such as inflation and a T-die method. The thickness of each layer described above can be performed by adjusting the amount of resin supplied when coextrusion film formation is performed. For example, when manufacturing a laminated film consisting of three layers, a surface layer, a laser coloring layer, and a colored layer, the film thickness is adjusted by controlling the supply amount of each resin using a three-type three-layer coextrusion film forming machine. I do.

<Laser marking method>
A method for forming a printed image on a multilayer film according to the present invention by laser marking will be described. When a laser beam is irradiated from the surface of the laminated film on which the surface layer is provided, the laser beam passes through the surface layer and reaches the laser coloring layer located therebelow. The color former that develops color by laser beam irradiation contained in the laser color development layer absorbs the energy of the laser beam, and the part irradiated with the laser beam develops color, for example, the laser printed image such as letters, numbers, symbols, and designs is very clear. Can be formed.

  In the present invention, the laser printed image formed as described above is protected by the surface layer or the colored layer located outside the laser coloring layer, so that the printed image is not affected externally. Also, the printed image is not lost by abrasion or rubbing by a solvent or the like. Therefore, it has a characteristic that it is extremely difficult to erase, counterfeit, alter, and modify a printed image, and the safety and reliability of laser marking can be improved.

When a carbon dioxide (CO ₂ ) laser (wavelength = 10.6 μm), which is usually used in laser printing, is used as the laser beam, the surface is cut and carbonized by irradiating the carbon dioxide (CO ₂ ) laser beam. Laser printing is not preferable because it emits smoke during irradiation, or because it is inferior in workability to a thin film, and further, a hole is easily generated in a laser printed image. This is not preferable because of such problems.

  In the present invention, the laser beam is a YAG (yttrium (Y) / aluminum (A) / garnet (G)) laser beam (wavelength = 1.064 μm) or a YVO4 (yttrium vanadate) laser beam (wavelength = 1.064 μm). It is preferable to perform laser printing using. The YAG laser beam has the property of transmitting through a transparent body. Utilizing this property, the laser coloring layer is sandwiched between layers made of other thermoplastic resins to suppress the generation of smoke, etc. By controlling the addition amount of the color former present therein and the film thickness of the laser color development layer, the color density and the influence on the laminated film can be adjusted. As a result, it is possible to form a very clear laser-printed image having no holes or the like even when a laser-printed image is formed.

<Packaging film>
The laminated film according to the present invention can be applied to, for example, the use of a heat-sealable resin layer (sealant layer) constituting a packaging sheet, and the like. For example, it can be used as a heat sealant layer at the time of bag making. . In order to produce a packaging material using a multilayer film as a heat-sealable resin layer, etc., the multilayer film according to the present invention and an arbitrary base material are laminated to produce a laminate having various forms. Can be used as a packaging film. In addition to the packaging material, depending on other members to be laminated, it can be applied to applications of cards, labels, business forms, and other industrial members.

Hereinafter, as an example, a packaging film using the laminated film of the present invention will be described.
As shown in FIG. 3, the packaging film is obtained by laminating a substrate 6 on the surface layer 1 side of the laminated film 5 according to the present invention. A printed pattern layer (not shown) made of desired characters, symbols, patterns, figures, etc. may be provided on the back surface of the substrate 6 (that is, the surface facing the surface layer 1). Alternatively, instead of providing a printed pattern layer on the back surface of the substrate 2, a printed pattern layer (not shown) composed of desired characters, symbols, patterns, figures, etc. may be provided on the surface of the surface layer 1 of the laminated film 5. Good.

  As the substrate, depending on the purpose and application of the packaging film, a laminate material may be used for 6 itself. For example, a substrate film such as a resin film, a paper substrate, oxygen gas or water vapor can be transmitted. Various substances such as a barrier base material to be blocked, cellophane, woven or non-woven fabric, and glass plate can be used, and two or more kinds of these base materials may be used in combination.

  As the resin film, a resin film or sheet having excellent properties in mechanical, physical and chemical properties, in particular, having strength and toughness, and heat resistance can be used. Specifically, for example, a film or sheet of tough resin such as polyester resin, polyamide resin, polyaramid resin, polyolefin resin, polycarbonate resin, polystyrene resin, polyacetal resin, or fluorine resin is used. be able to. As the resin film, any of an unstretched film and a stretched film stretched in a uniaxial direction or a biaxial direction can be used. Moreover, as thickness of a resin film, about 5-100 micrometers is preferable, More preferably, it is about 10-50 micrometers.

As a paper base material, it has formability, bending resistance, rigidity, etc., for example, a paper base material with high sizing property or unbleached paper, or pure white roll paper, kraft paper, paperboard, processed paper A paper base material such as can be used. It is preferable to use a paper base having a basis weight of about 80 to 600 g / m ² , more preferably a basis weight of about 100 to 450 g / m ² .

  As the barrier substrate, a film or sheet of a resin such as low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer having barrier properties such as water vapor and water Is mentioned. Examples of the barrier base material that prevents permeation of oxygen gas, water vapor, and the like include, for example, polyvinylidene chloride resin, polyvinyl alcohol resin, saponified ethylene-vinyl acetate copolymer, MXD nylon 6 resin, and other barrier properties. Resin film or sheet, aluminum foil or aluminum vapor deposited resin film, silicon oxide, resin film having a vapor deposited film of inorganic oxide such as aluminum oxide (by physical vapor deposition method or chemical vapor deposition method), resin Examples thereof include a film or sheet of a light-shielding colored resin obtained by adding a colorant such as a pigment and a desired additive and kneading to form a film.

  These materials can be used alone or in combination of two or more. The thickness of the barrier substrate is arbitrary, but is usually about 5 to 300 μm, and preferably about 10 to 100 μm.

  In addition, the packaging film is subject to severe physical and chemical conditions when the packaged bag is applied to various applications. From the various viewpoints such as properties, heat resistance, sealing properties, quality maintenance, workability, hygiene, and the like, a substrate can be arbitrarily selected and used. Specifically, for example, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl acrylate. Copolymer, ethylene-acrylic acid or methacrylic acid copolymer, methylpentene polymer, polybutene resin, polyvinyl chloride resin, polyvinyl acetate resin, polyvinylidene chloride resin, vinyl chloride-vinylidene chloride copolymer, Poly (meth) acrylic resin, polyacrylonitrile resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyester resin, polyamide resin Resin, Polycar Nate resin, polyvinyl alcohol resin, saponified ethylene-vinyl acetate copolymer, fluorine resin, diene resin, polyacetal resin, polyurethane resin, film or sheet of a known resin such as nitrocellulose. You can select and use.

  When the base material 2 as described above is laminated on the laminated film, the laser beam can sufficiently reach the laser coloring layer 2 of the laminated film 5 and the laser-marked printed image can be easily visually recognized from the outer surface. Furthermore, it is preferable not to provide a printed pattern layer in the area where laser marking is to be performed. For the same reason as above, as shown in FIG. 4, when using a material that does not easily transmit laser light as a substrate, or when using a material that cannot visually recognize a laser-marked printed image, It is preferable to provide the window 7 in an area corresponding to the area to be laser-marked.

Next, a method for producing a packaging film using the laminated film according to the present invention will be described.
As a method of laminating a substrate on a laminated film, a dry laminate laminating method in which a laminated film and a substrate are laminated via a primer agent layer or an adhesive layer for lamination, a primer agent layer or an anchor coat agent layer, etc. Thus, a film for packaging can be produced using an extrusion laminating method in which a desired base material is arbitrarily laminated by melt extrusion of various resins or the like, or other laminating methods.

  To illustrate a specific example of the dry laminate lamination method, first, a printed pattern layer composed of desired characters, symbols, patterns, figures, etc. is formed on one surface of the substrate, and the printed pattern layer and the surface layer of the laminated film And the substrate and the laminated film are overlapped with each other via a laminating adhesive layer or the like. Alternatively, instead of forming a printed pattern layer or the like on the back surface of the substrate as described above, a printed pattern layer composed of desired characters, symbols, patterns, figures, etc. is formed on the surface layer of the laminated film, and the substrate The base material and the laminated film may be overlapped with each other via an adhesive layer for lamination so that the surface-treated surface and the surface layer of the laminated film face each other. The base material surface may be subjected to pretreatment such as corona treatment or ozone treatment in order to make the adhesion stronger.

  The printed pattern layer is mainly composed of one or more kinds of ordinary ink vehicles, and if necessary, a plasticizer, a stabilizer, an antioxidant, a light stabilizer, an ultraviolet absorber, a curing agent, a crosslinking agent. Add one or more additives such as additives, lubricants, antistatic agents, fillers, etc., add colorants such as dyes and pigments, and knead thoroughly with solvents, diluents, etc. Using the ink composition prepared, for example, using gravure printing, offset printing, letterpress printing, screen printing, transfer printing, flexographic printing, etc., on the substrate or laminated film, characters, figures, It can be formed by printing a desired printed pattern consisting of symbols, patterns, and the like. In addition, a printed pattern layer may form a printed pattern layer on a lamination adhesive bond layer or an anchor coating agent layer.

  Examples of laminating adhesives include, for example, polyvinyl acetate adhesives, homopolymers of ethyl acrylate, butyl, 2-ethylhexyl ester, and copolymers of these with methyl methacrylate, acrylonitrile, styrene, etc. Polyacrylic acid ester adhesives, cyanoacrylate adhesives, ethylene copolymer adhesives made of copolymers of ethylene and monomers such as vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid, etc., cellulose Adhesives, polyester adhesives, polyamide adhesives, polyimide adhesives, amino resin adhesives made of urea resin or melamine resin, phenol resin adhesives, epoxy adhesives, polyurethane adhesives, reactive type (Meth) acrylic adhesive, chloroprene rubber, nitrile rubber , Styrene - butadiene rubber consisting of such as a rubber-based adhesive, silicone adhesive, an alkali metal silicate, may be used adhesives inorganic adhesive or the like made of a low-melting-point glass or the like.

  The composition system of the above-mentioned adhesive may be any composition form such as an aqueous type, a solution type, an emulsion type, and a dispersion type, and the property is any of film / sheet form, powder form, solid form, etc. Further, the bonding mechanism may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a hot pressure type and the like.

The adhesive can be applied by, for example, a roll coating method, a gravure roll coating method, a coating method such as a kiss coating method, or a printing method, and the coating amount is 0.1 to 10 g / m ² (dry state). ) Degree is preferred.

  Examples of the primer layer include polyurethane resins, polyester resins, polyamide resins, epoxy resins, phenol resins, (meth) acrylic resins, polyvinyl acetate resins, and polyolefin resins such as polyethylene aly polypropylene. Alternatively, the primer agent layer can be formed using a resin composition containing the copolymer or a modified resin, a cellulose resin, or the like as a main component of the vehicle.

The primer layer can be formed by, for example, applying the above-described composition using a coating method such as roll coating, gravure roll coating, kiss coating, etc. to form a primer coating agent layer. About 10 to 10 g / m ² (dry state) is preferable.

  Next, exemplifying specific examples of the extrusion laminating method, first, a printed pattern layer composed of desired characters, symbols, designs, figures, etc. is formed on one surface of a substrate, and an anchor coat is formed thereon. The agent is coated by a gravure roll coating method or the like to form an anchor coating agent layer. Next, while extruding a heat-melting resin such as low-density polyethylene, the hot-melt extruded resin so that the surface of the anchor coating agent layer of the base material and the surface layer of the laminated film face each other. Overlay through layers. Alternatively, instead of forming a printed pattern layer or the like on the back surface of the substrate as described above, a printed pattern layer composed of desired characters, symbols, patterns, figures, etc. may be formed on the surface layer of the laminated film. . The base material surface may be subjected to pretreatment such as corona treatment and ozone treatment in order to make the adhesion stronger.

As the anchor coating agent constituting the anchor coating agent layer, for example, various water-based or oil-based anchor coating agents such as organic titanium-based, isocyanate-based, polyethyleneimine-based, polyptadiene-based, such as alkyl titanate can be used. The anchor coating agent can be applied using, for example, a coating method such as roll coating, gravure roll coating, kiss coating, and the coating amount is about 0.1 to 5 g / m ² (dry state). preferable.

  Examples of the melt-extruded resin layer in the extrusion laminating method include, for example, polyethylene resins, polypropylene resins, acid-modified polyethylene resins, acid-modified polypropylene resins, ethylene-acrylic acid or methacrylic acid copolymers, Surlyn resins, and ethylene. -Use one or more thermoplastic resins such as vinyl acetate copolymer, polyvinyl acetate resin, ethylene-acrylic acid ester or methacrylic acid ester copolymer, polystyrene resin, and polyvinyl chloride resin. Can do. In the extrusion laminating method, in order to obtain stronger adhesive strength, stronger adhesive strength can be realized by laminating via the anchor coating agent. In the present invention, a printed pattern layer may be formed on the laminate adhesive layer or anchor coat agent layer.

<Packaging body>
Next, a package using the packaging film described above will be described. As an example of a packaging body, a packaging bag using a packaging film will be described, but the present invention is not limited to these uses, and depending on the purpose, use, etc., a flexible packaging bag, a liquid paper container, It goes without saying that various types of packaging containers such as paper cans can be manufactured.

  When the packaging bag is a soft packaging bag made of a plastic film or the like, it is folded so that the colored layer 3 or the heat seal layer 4 which is the inner layer of the packaging film is opposed, or two of them are overlapped, Subsequently, the packaging bag can be manufactured by heat-sealing the peripheral edge of the packaging film. Heat seal includes side seal type, two-side seal type, three-side seal type, four-side seal type, envelope-attached seal type, palm-attached seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, etc. It can be made the form. As a heat sealing method, for example, a known method such as a bar seal, a rotary roll seal, a belt seal, an impulse seal, a high frequency seal, or an ultrasonic seal can be used.

  As a form of the packaging bag, in addition to the general bag form as described above, a self-supporting packaging bag (standing pouch) or a tube container can be used. Further, for example, a spout such as a one-piece type or a two-piece type, or a zipper for opening and closing can be arbitrarily attached to the packaging bag.

  As a packaging bag, in the case of a liquid-filled paper container containing a paper base material, a blank board for producing a desired paper container is produced, and the trunk, bottom, head, etc. are boxed using the blank board, For example, a liquid type container such as a brick type, a flat type, or a gable top type can be manufactured. As the shape of the container, any one of a rectangular container, a cylindrical paper can such as a round shape, and the like can be manufactured.

  The packaging bags produced as described above are, for example, various foods, fruit juices, juices, drinking water, liquor, cooked foods, marine products, frozen foods, meat products, boiled foods, rice cakes, liquid soups, seasonings, etc. It can be filled and packaged with food / beverage products, liquid detergents, cosmetics, chemicals, and other items.

  In the present invention, in particular, for example, a liquid sachet for filling and packaging soy sauce, sauce, soup, etc., a soft packaging bag for filling and packaging fresh confectionery, etc., or a soft packaging bag for filling and packaging boiled or retort foods, etc. It is useful as a packaging container for filling and packaging liquid food and drink or food and drink containing moisture.

  For example, filling the contents such as food and drink from the opening of the three-side seal type packaging bag produced above, then heat-sealing the upper opening to form the upper seal, etc. Accordingly, for example, a boil treatment, a retort treatment, and the like can be performed to manufacture a packaged product having various forms.

  Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these examples.

(1) Production of laminated film As a resin composition for the surface layer, an ethylene-α / olefin copolymer polymerized using a single site catalyst (metallocene catalyst) (manufactured by Prime Polymer Co., Ltd., trade name: Evolu SP2020) , Density = 0.916 g / cm ³ , MFR = 1.5 g / 10 min). Further, as the resin composition for the laser coloring layer, 90 parts by weight of the same ethylene-α / olefin copolymer as described above and 10 parts by weight of YAG laser coloring pigment (manufactured by Merck & Co., trade name: Lazerflair 825) A sufficiently kneaded product was used. The resin composition for the colored layer was prepared by sufficiently kneading 90 parts by weight of the same ethylene-α / olefin copolymer as described above and 10 parts by weight of titanium oxide as a white pigment. Further, as the resin composition for the back layer, the same ethylene-α / olefin copolymer as described above was used.
Using each of the resin compositions described above, a film in which a surface layer, a laser coloring layer, a colored layer, and a back layer were laminated in this order was produced by a four-type four-layer top-blown air-cooled inflation coextrusion film-forming machine. When the film was formed by the coextrusion film forming machine, the film was coextruded so that the surface layer was 5 μm, the laser coloring layer was 20 μm, the colored layer was 15 μm, and the back layer was 10 μm to obtain a laminated film having a total thickness of 50 μm. .

(2) Print test on film Using the YVO4 laser beam irradiation device (Keyence Corporation YVO4 laser marker MD-V9600A) from the surface layer side of the laminated film obtained above, YVO4 laser light was output at 13 W. Irradiated. As a result, it was confirmed that the portion irradiated with the laser was colored black and a laser-printed image could be formed. During laser printing, no smoke was generated, and no hole was found in the laminated film.

  The degree of color development of the printed image was evaluated by visually observing the printed image from the surface layer side. The evaluation criteria were as follows.

Excellent: Print color is particularly dense. Good: Print color is dense. Normal: Coloring to the extent that printing is not impaired can be confirmed. Bad: Not sufficiently colored. The evaluation results are as shown in Table 1 below.

  In addition, in order to evaluate the visibility of a printed image when a package body made of a laminated film is filled with contents or when the laminated film is laminated with another member, the laminated film subjected to the above laser printing is used as a surface layer. The printed image was visually observed from the surface layer side. The evaluation criteria were as follows.

Excellent: Particularly good visual recognition Good: Good visual recognition Normal: No problem in visual recognition Bad: Difficult to visually evaluate The evaluation results are as shown in Table 1 below.

  As a resin composition for the laser coloring layer, 95 parts by weight of the same ethylene-α / olefin copolymer as described above and 5 parts by weight of YAG laser coloring pigment (trade name: Lazerflair 825, manufactured by Merck & Co., Ltd.) A laminated film was produced in the same manner as in Example 1 except that the kneaded one was used.

When the obtained laminated film was used for the same evaluation as in Example 1, it was confirmed that the portion irradiated with the laser was colored black and a laser-printed image could be formed. During laser printing, no smoke was generated and no holes were found in the laminated film.
The evaluation results of the printed image are as shown in Table 1 below.

  As a resin composition for the laser coloring layer, 80 parts by weight of the same ethylene-α / olefin copolymer as described above and 20 parts by weight of YAG laser coloring pigment (trade name: Lazerflair 825, manufactured by Merck Ltd.) A kneaded mixture is used, and a resin composition for the colored layer is prepared by sufficiently kneading 80 parts by weight of the same ethylene-α / olefin copolymer and 20 parts by weight of titanium oxide as a white pigment. In addition, when the film is formed by a coextrusion film forming machine, the surface layer is 5 μm, the laser coloring layer is 10 μm, the colored layer is 5 μm, and the back layer is 20 μm, so that the total thickness is 40 μm. A laminated film was produced in the same manner as in Example 1 except that.

When the obtained laminated film was used for the same evaluation as in Example 1, it was confirmed that the portion irradiated with the laser was colored black and a laser-printed image could be formed. During laser printing, no smoke was generated and no holes were found in the laminated film.
The evaluation results of the printed image are as shown in Table 1 below.

  As a resin composition for the laser coloring layer, 80 parts by weight of the same ethylene-α / olefin copolymer as described above and 20 parts by weight of YAG laser coloring pigment (trade name: Lazerflair 825, manufactured by Merck Ltd.) When using a kneaded material, and when forming a film with a coextrusion film forming machine, coextrusion film formation is performed so that the surface layer is 5 μm, the laser coloring layer is 10 μm, the colored layer is 10 μm, and the back layer is 15 μm. A laminated film was produced in the same manner as in Example 1 except that the total thickness was 40 μm.

When the obtained laminated film was used for the same evaluation as in Example 1, it was confirmed that the portion irradiated with the laser was colored black and a laser-printed image could be formed. During laser printing, no smoke was generated and no holes were found in the laminated film.
The visibility evaluation of the printed image was as shown in Table 1 below.

  As the resin composition for the colored layer, a mixture obtained by sufficiently kneading 80 parts by weight of the same ethylene-α / olefin copolymer as described above and 20 parts by weight of titanium oxide as a white pigment is used. Example 1 except that the film was co-extruded so that the surface layer was 5 μm, the laser coloring layer was 10 μm, the colored layer was 5 μm, and the back layer was 20 μm to a total thickness of 40 μm. A laminated film was produced in the same manner.

When the obtained laminated film was used for the same evaluation as in Example 1, it was confirmed that the portion irradiated with the laser was colored black and a laser-printed image could be formed. During laser printing, no smoke was generated and no holes were found in the laminated film.
The evaluation results of the printed image are as shown in Table 1 below.

  When the film was formed by the coextrusion film forming machine, the surface layer was 5 μm, the laser coloring layer was 10 μm, the colored layer was 10 μm, and the back layer was 15 μm. A laminated film was produced in the same manner as in Example 1.

When the obtained laminated film was used for the same evaluation as in Example 1, it was confirmed that the portion irradiated with the laser was colored black and a laser-printed image could be formed. During laser printing, no smoke was generated and no holes were found in the laminated film.
The evaluation results of the printed image are as shown in Table 1 below.

  As a resin composition for the laser coloring layer, 92.5 parts by weight of the same ethylene-α / olefin copolymer as described above and 7.5 parts by weight of YAG laser coloring pigment (trade name: Lazerflair 825, manufactured by Merck & Co., Inc.) And 80 parts by weight of the same ethylene-α / olefin copolymer as described above as a resin composition for the colored layer, and 20 parts by weight of titanium oxide as a white pigment. Using the kneaded material, and when forming a film with a coextrusion film forming machine, co-extrusion film formation so that the surface layer is 5 μm, the laser coloring layer is 15 μm, the colored layer is 5 μm, and the back layer is 15 μm, A laminated film was produced in the same manner as in Example 1 except that the total thickness was 40 μm.

When the obtained laminated film was used for the same evaluation as in Example 1, it was confirmed that the portion irradiated with the laser was colored black and a laser-printed image could be formed. During laser printing, no smoke was generated and no holes were found in the laminated film.
The evaluation results of the printed image are as shown in Table 1 below.

  As a resin composition for the laser coloring layer, 92.5 parts by weight of the same ethylene-α / olefin copolymer as described above and 7.5 parts by weight of YAG laser coloring pigment (trade name: Lazerflair 825, manufactured by Merck & Co., Inc.) In addition, when the film is formed by a coextrusion film forming machine, the surface layer is 5 μm, the laser coloring layer is 15 μm, the colored layer is 10 μm, and the back layer is 10 μm. A laminated film was produced in the same manner as in Example 1 except that the film was formed to have a total thickness of 40 μm.

When the obtained laminated film was used for the same evaluation as in Example 1, it was confirmed that the portion irradiated with the laser was colored black and a laser-printed image could be formed. During laser printing, no smoke was generated and no holes were found in the laminated film.
The evaluation results of the printed image are as shown in Table 1 below.

One side of a 12 μm thick biaxially stretched polyethylene terephthalate film is subjected to corona discharge treatment, and a two-component curable polyurethane laminate adhesive is applied to the thickness of 3.0 g / m ² (dry) on the corona discharge treatment surface. An adhesive layer is formed by coating, and a biaxially stretched nylon film having a corona treatment on both sides is superposed on the surface of the adhesive layer, and then on the surface of the biaxially stretched nylon film. A base film was obtained by applying a two-component curable polyurethane-based laminate adhesive to a thickness of 3.0 g / m ² (dry) to form an adhesive layer.

The surface of the surface layer of the laminated film obtained in the same manner as in Example 1 is subjected to corona discharge treatment, and the surface layer and the adhesive layer of the base film obtained above are bonded to face each other. Thus, a laminated film provided with a base film was produced.
When the obtained laminated film was used for the same evaluation as in Example 1, it was confirmed that the portion irradiated with the laser was colored black and a laser-printed image could be formed. During laser printing, no smoke was generated and no holes were found in the laminated film.
The evaluation results of the printed image are as shown in Table 1 below.

Comparative Example 1

  As the resin composition for the surface layer, the same ethylene-α / olefin copolymer as described above is used, and as the resin composition for the laser coloring layer, the same ethylene-α / olefin copolymer as described above is used at 80 weight. Part and 20 parts by weight of YAG laser coloring pigment (manufactured by Merck & Co., Ltd., trade name: Lazerflair 825) were sufficiently kneaded. Further, as the resin composition for the back layer, the same ethylene-α as described above was used. -Olefin copolymer was used.

  Using each of the resin compositions described above, a film in which a surface layer, a laser coloring layer, and a back layer were laminated in this order was produced using a three-type, three-layer, top-blown air-cooled inflation coextrusion film forming machine. When the film was formed by the coextrusion film forming machine, the film was coextruded so that the surface layer was 15 μm, the laser coloring layer was 10 μm, and the back layer was 15 μm, to obtain a laminated film having a total thickness of 40 μm.

When the obtained laminated film was used for the same evaluation as in Example 1, it was confirmed that the portion irradiated with the laser was colored black and a laser-printed image could be formed. During laser printing, no smoke was generated and no holes were found in the laminated film.
The evaluation results of the printed image are as shown in Table 1 below.

Comparative Example 2

  As a resin composition for the laser coloring layer, 90 parts by weight of the same ethylene-α / olefin copolymer as described above and 10 parts by weight of YAG laser coloring pigment (trade name: Lazerflair 825, manufactured by Merck Ltd.) A laminated film was produced in the same manner as in Comparative Example 1 except that the kneaded one was used.

When the obtained laminated film was used for the same evaluation as in Example 1, it was confirmed that the portion irradiated with the laser was colored black and a laser-printed image could be formed. During laser printing, no smoke was generated and no holes were found in the laminated film.
The evaluation results of the printed image are as shown in Table 1 below.

Comparative Example 3

  As a resin composition for the laser coloring layer, 92.5 parts by weight of the same ethylene-α / olefin copolymer as described above and 7.5 parts by weight of YAG laser coloring pigment (trade name: Lazerflair 825, manufactured by Merck & Co., Inc.) In addition, when forming a film with a coextrusion film forming machine, the film is coextruded so that the surface layer is 10 μm, the laser coloring layer is 15 μm, and the back layer is 15 μm. A laminated film was produced in the same manner as in Comparative Example 1 except that the thickness was 40 μm.

When the obtained laminated film was used for the same evaluation as in Example 1, it was confirmed that the portion irradiated with the laser was colored black and a laser-printed image could be formed. During laser printing, no smoke was generated and no holes were found in the laminated film.
The evaluation results of the printed image are as shown in Table 1 below.

Comparative Example 4

  As a resin composition for the laser coloring layer, 99 parts by weight of the same ethylene-α / olefin copolymer as described above and 1 part by weight of a YAG laser coloring pigment (trade name: Lazerflair 825, manufactured by Merck Ltd.) When using a kneaded material, and when forming a film with a coextrusion film forming machine, coextrusion film formation is performed so that the surface layer is 5 μm, the laser coloring layer is 10 μm, the colored layer is 10 μm, and the back layer is 15 μm. A laminated film was produced in the same manner as in Example 1 except that the total thickness was 40 μm.

Using the obtained laminated film, the same evaluation as in Example 1 was performed, and it was confirmed that the portion irradiated with the laser was very slightly colored black and a laser-printed image could be formed. During laser printing, no smoke was generated and no holes were found in the laminated film.
The evaluation results of the printed image are as shown in Table 1 below.

Comparative Example 5

  As the resin composition for the surface layer, the same ethylene-α / olefin copolymer as described above is used, and as the resin composition for the laser coloring layer, the same ethylene-α / olefin copolymer as described above is used at 90 weight. Part and YAG laser coloring pigment (Merck Co., Ltd., trade name: Lazerflair 825) 10 parts by weight sufficiently kneaded, and as a resin composition for the colored layer, the same ethylene-α as described above A material obtained by sufficiently kneading 90 parts by weight of an olefin copolymer and 10 parts by weight of titanium oxide as a white pigment was used.

  Using each of the resin compositions described above, a film in which a surface layer, a colored layer, and a laser coloring layer were laminated in this order was produced by a three-type three-layer top-blown air-cooled inflation co-extrusion film forming machine. When the film was formed by the coextrusion film forming machine, the film was coextruded so that the surface layer was 20 μm, the colored layer was 15 μm, and the laser coloring layer was 15 μm, to obtain a laminated film having a total thickness of 50 μm.

  When the same evaluation as in Example 1 was performed using the obtained laminated film, the portion irradiated with the laser was not clearly colored, but the colored layer portion and the mount were slightly burned, so the color was extremely thin. Was. During laser printing, no smoke was generated and no holes were found in the laminated film.

The evaluation results of the printed image are as shown in Table 1 below.

The schematic sectional drawing of the laminated | multilayer film of this invention is shown. The laminated film schematic sectional drawing of another aspect of this invention is shown. The schematic sectional drawing of the film for packaging using a laminated film is shown. The schematic sectional drawing of the film for packaging of another aspect using a laminated | multilayer film is shown.

Explanation of sign

1. Surface layer 2. Laser coloring layer 3. Colored layer 4. Heat seal layer Laminated film 6. Base material 7. window

Claims (9)

At least a laser coloring layer that develops color by laser light irradiation, a surface layer provided on a laser light irradiation side of the laser coloring layer, and a colored layer provided on a side opposite to the laser light irradiation side, A laminated film comprising:
The laser coloring layer is made of a thermoplastic resin containing a laser coloring agent,
The laser color former is contained in an amount of 5 to 50% by weight based on the thermoplastic resin,
A laminated film having a total thickness of 8 to 120 μm.   The laminated film according to claim 1, wherein the laser coloring layer has a thickness of 1 to 50 μm.   The laminated film according to claim 1 or 2, wherein the colored layer has a thickness of 1 to 50 µm.   The laminated film according to any one of claims 1 to 3, wherein the surface layer has a thickness of 1 to 100 µm.   The laminated film according to any one of claims 1 to 4, wherein a ratio between the thickness of the laser coloring layer and the thickness of the colored layer is 1: 4 to 15: 1.   The laminated film according to any one of claims 1 to 5, wherein the laminated film is formed by coextrusion molding.   The laminated film according to any one of claims 1 to 6, wherein the surface layer is made of a transparent thermoplastic resin.   The laminated film according to any one of claims 1 to 7, wherein a heat seal layer is provided on the side of the colored layer opposite to the laser coloring layer side.   The packaging film using the laminated | multilayer film as described in any one of Claims 1-8.

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